Invistools — Fast & Secure Client-side Micro Tools

⭐

555 Timer Calculator

Calculate astable frequency, duty cycle, charge and discharge time, or monostable pulse width for a 555 timer.

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Add Prefix and Suffix to Lines

Wrap every line of a list with custom prefix and suffix text instantly and privately in your browser.

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Age Calculator — How Old Am I?

Calculate your exact age in years, months and days from your date of birth, plus a countdown to your next birthday.

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Air Fryer Converter — Oven to Air Fryer Settings

Convert oven temperature and time to air fryer settings (or back), using the standard −25°F/−15°C, 20-25% less time rule of thumb, plus a lookup table for common foods.

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Online Alarm Clock

Set a wake-up time and get a live countdown, a looping generated melody, a full-screen notice and a blinking tab title when the moment arrives — right in the browser tab.

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Anagram Solver

Find exact anagrams of a word or discover every word you can make from a set of letters, checked against an English dictionary word list.

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Angel Number Meaning

Decode a number you keep seeing — 111, 12:12, 777 — digit by digit, with its core number and repeating patterns.

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Area Converter

Convert area units instantly: square millimeters to square kilometers, hectares, square feet, square inches and acres.

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Aspect Ratio Calculator

Calculate the missing side for any aspect ratio — 16:9, 4:3, 21:9, 1:1 or custom — or simplify the ratio of two known dimensions.

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Audio Analyzer

Audio Analyzer helps you work precisely with levels, loudness, and stereo analysis in the browser.

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MP3 to WAV / WAV to MP3

Local audio conversion between MP3 and WAV directly in the browser without downloading to the server.

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Audio Key Detector

Estimate the musical key of an uploaded audio file with local browser analysis.

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Merge Audio

Combine multiple audio files into one track right in the browser quickly and confidentially.

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Audio Normalizer

Equalize the volume level of audio files to the optimal standard without losing quality.

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Audio Scale Converter

Audio Scale Converter helps you work precisely with levels, loudness, and stereo analysis in the browser.

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Audio File Spectrogram

Audio File Spectrogram shows the frequency content of sound directly in the browser without uploading it to a server.

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Audio Speed and Pitch

Flexibly change playback speed and audio pitch locally in the browser.

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Trim Audio

Cut desired fragments from audio files instantly and safely right in the browser.

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Average Calculator

Paste a list of numbers and get the mean, median, mode, range, sum, min and max at once — or compute a weighted average with full steps.

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BAC Calculator (Widmark Formula)

Estimate blood alcohol content from your drinks, body weight, sex and time elapsed using the classic Widmark formula, with every number shown — for education only, never for deciding whether to drive.

⭐

Band Name Generator

Generate ten band name ideas per click from curated word lists, with rock, metal, indie and punk flavor packs and click-to-copy.

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Barcode Generator

Generate Code 128, EAN-13, EAN-8, UPC-A and Code 39 barcodes with live validation and automatic check digits, downloadable as SVG or PNG.

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Base64 / Hex / Binary Multi-Coder

Convert text or binary files to Base64, Hexadecimal, Binary representation and back.

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Calculator

A convenient web calculator for quick mathematical calculations in a stylish design.

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Bass Guitar Scale Fingering

Scale patterns for 4-string bass by position: one-finger-per-fret or Simandl 1-2-4 fingering, with roots, note names and degrees on the fretboard.

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Bingo Card Generator

Turn any 24+ item list — or a built-in Christmas, baby shower or icebreaker set — into unique 3x3, 4x4 or 5x5 bingo cards, ready to print.

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Biorhythm Calculator

Plot your physical, emotional and intellectual biorhythms around any date on an interactive chart.

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Birth Year Calculator

Find the year someone was born from their current age — with both possible years shown when you are not sure whether their birthday has passed.

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Birthday Compatibility Calculator

Compare two birth dates by numerology: life path numbers, concord groups and a compatibility score.

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Blur Image

Blur or pixelate selected parts of a photo by drawing rectangles over them — locally in your browser.

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BMI Calculator

Calculate your Body Mass Index in metric or imperial units and see your WHO category on a color scale, entirely in your browser.

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Body Fat Calculator (US Navy Method)

Estimate your body fat percentage from tape measurements with the US Navy method, see your ACE category and fat/lean mass — right in your browser.

⭐

Body Frame Size Calculator

Find your skeletal frame size — small, medium or large — from height and wrist circumference using the classic height-to-wrist ratio heuristic, right in your browser.

⭐

Border Radius Generator

Design CSS border-radius visually: four independent corner sliders in px or percent, a link-all-corners shortcut for instant circles and pills, plus an organic blob mode with randomized shapes.

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Violin, Cello and Double Bass Scale Fingering

First-position scale fingerings for violin, viola, cello, and double bass: which finger plays each note, on which string, with low and high placements marked.

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Tap BPM Counter

Determine the tempo of music (BPM) in real time with simple keystrokes.

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Bra Size Calculator & Converter

Estimate your bra size from underbust and bust measurements, or convert an existing size between US, UK, EU, FR and IT — plus its sister sizes.

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Break-Even Calculator

Find the exact unit volume and revenue where fixed and variable costs stop exceeding sales, with a margin-of-safety readout and a revenue-vs-cost chart.

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Business Days Calculator

Count weekdays between two dates while excluding weekends and an optional custom holiday list.

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Caffeine Half-Life Calculator

Model how caffeine from your coffee, tea or energy drink decays over the next 12 hours and see how much is likely left when you go to bed.

⭐

Monthly Calendar Generator

Generate a clean monthly calendar with Monday or Sunday as the first day of the week and print it.

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Calorie Calculator (BMR & TDEE)

Calculate your BMR, TDEE and daily calorie targets for weight loss, maintenance or gain with the Mifflin-St Jeor formula — right in your browser.

⭐

Case Converter

Instant text case conversion: uppercase, lowercase, transliteration and URL slug generation.

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Cat Age Calculator (Cat Years to Human Years)

Convert your cat's age to human years with the AAHA/AAFP veterinary scale and see its life stage from kitten to geriatric — entirely in your browser.

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Certificate & CSR Decoder (X.509 / PKCS#10)

Paste a PEM-encoded X.509 certificate or PKCS#10 CSR and see every field decoded — subject, issuer, validity, SANs, public key and fingerprint — entirely offline.

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Certificate Generator

Create a print-ready certificate of achievement or completion — recipient name, course title, issuing organization, date and a signature line, drawn as a real vector design entirely offline.

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Character Counter

Live character count with platform limits: Twitter/X, Instagram, LinkedIn, YouTube titles, meta descriptions and real SMS segment math.

⭐

Charades Word Generator

Deal charades words from a no-repeat deck: six categories, easy and hard levels, and a built-in round timer with a beep.

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Child Growth Percentile Calculator (LMS Method)

Estimate a child's height or weight percentile using the real LMS statistical method behind official growth charts — entirely in your browser.

⭐

Chinese Zodiac Calculator

Find your Chinese zodiac animal, element and yin-yang polarity — with the Lunar New Year boundary handled correctly.

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Chmod Calculator

Convert Linux file permissions between rwx checkboxes, octal numbers and symbolic notation with a ready chmod command.

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Chord Chart Transposer

Paste a chord chart with lyrics and shift every chord by semitones, with a real chord-symbol parser and enharmonic-aware sharp/flat spelling.

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Chord Key Finder

Find likely major or minor keys from a typed chord progression with scale-degree labels.

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Chroma Key Remover

Pick a flat green screen, blue screen or solid background color with an eyedropper and make it transparent, using real YCbCr chroma-distance keying.

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Chronological Age Calculator (Y;M;D)

Calculate exact chronological age as of any reference or test date — not just today — in the clinical Y;M;D notation used on assessment forms, with the borrow-method steps shown.

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Circle Calculator

Enter any one measure of a circle — radius, diameter, circumference or area — and get the other three instantly, with every formula shown with your numbers substituted in.

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Photo in Circle

Create beautiful round avatars with frames and gradient backgrounds completely offline.

⭐

Clothing Size Converter

Convert clothing sizes between US, UK, EU, Italian, French, Japanese and international S–XXL scales for dresses, shirts, suits and trousers.

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Code Formatter

Fast alignment and formatting of HTML, CSS, JavaScript and TypeScript code offline.

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Code Minifier

Minify CSS, JavaScript, HTML or JSON in the browser: strip comments and whitespace, see the size saved instantly.

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Coin Flip — Flip a Coin Online

Flip a virtual coin with a 3D animation, fair crypto randomness, and a running heads/tails counter.

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Collage Maker

Place images on standard paper sizes (A4, A3, Letter) for printing.

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Color Blindness Simulator

See a photo, chart or screenshot the way someone with protanopia, deuteranopia, tritanopia or achromatopsia would, using published color-vision-deficiency transform matrices applied in linear RGB.

⭐

Color Format Converter

Convert any color between HEX, RGB, HSL and CMYK notation with a live preview swatch — right in your browser.

⭐

Color Palette Generator

Create harmonious color palettes from a base color and export CSS codes.

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Color Code Translator & Contrast Matrix

Convert color models between HEX, RGB, HSL, CMYK, and LCH, check WCAG contrast compliance, and blend colors in LCH space.

⭐

Compound Interest Calculator

See how an investment grows with compound interest: final balance, total contributed and interest earned, with a year-by-year growth table.

⭐

Concrete Calculator — Bags Needed for Slabs, Footings & Posts

Work out how much concrete a slab, footing, column pour or a batch of fence post holes needs: pick the shape, enter its real dimensions, and get the volume in cubic yards and cubic meters plus the number of pre-mixed bags to buy.

⭐

Connect Four AI — Play Against a Minimax Engine

Play Connect Four against a real AI opponent that searches the game tree with negamax and alpha-beta pruning, backed by a genuine center-weighted position heuristic — pick your color and difficulty and drop discs on an animated board.

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Contact Sheet Generator

Automatically arrange a batch of photos into a uniform thumbnail grid with burned-in frame numbers or filenames — the classic photographer's contact/proof sheet.

⭐

Cooking Measurement Converter

Convert cups, tablespoons, teaspoons, milliliters, grams and ounces with real ingredient densities — because a cup of flour does not weigh a cup of sugar.

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Countdown Timer

Simple and stylish countdown timer with completion sound.

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CPS Test — Click Speed Test

Measure your clicks per second in a kohi-style click test with a live counter and an animal rank from turtle to cheetah.

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Cron Validator

Offline syntax checking of Cron expressions with human-language interpretation of the schedule.

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Crontab Generator

Build cron expressions with dropdowns and instantly see a plain-language schedule plus the next 5 real run times.

⭐

CSS Animated Gradient Border Generator

Generate a smoothly rotating rainbow gradient border that correctly respects border-radius, built with @property, conic-gradient and mask-composite — copy the real CSS, watch it spin live.

⭐

CSS Box Shadow Generator

Build CSS box-shadow code visually: sliders for offset, blur, spread, color with opacity, inset mode and up to four layers with a live preview.

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CSS Clamp() Calculator

Compute a real fluid CSS clamp() value from a min and max size across two viewport widths, with the slope and intersection shown step by step and a live resize preview.

⭐

CSS Clip-Path Generator

Draw arbitrary polygon shapes — including concave notches — by dragging points on a live preview box or your own uploaded image, and copy the resulting CSS clip-path: polygon(...) value.

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CSS Filter Generator

Build a reorderable chain of CSS filter() and backdrop-filter() functions and preview it live on your own uploaded photo, with a copyable CSS line and PNG export.

⭐

CSS Flexbox Generator

Build a CSS flexbox layout visually: flex-direction, justify-content, align-items, flex-wrap and gap on the container, plus per-child flex-grow, flex-shrink and flex-basis, all with a live preview and copyable CSS.

⭐

CSS Gradient Generator

Build CSS gradients visually: linear, radial or conic type, angle slider and up to six color stops with a live full-width preview and copyable code.

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CSS Grid Generator

Design CSS Grid layouts visually: set columns, rows and gap, then type area names into cells to build grid-template-areas — with a live preview and copyable CSS and HTML.

⭐

CSS Keyframe Animation Generator

Build real @keyframes animations on a multi-track timeline — transform, opacity and background-color stops per track — with a draggable playhead that shows the exact interpolated mid-animation state.

⭐

CSS Pattern Background Generator

Build tileable stripes, dots, checkerboard, grid, diagonal crosshatch and triangle backgrounds from real layered CSS gradients — zero images — or export the same pattern as an SVG <pattern> for use inside SVG documents.

⭐

CSS Scrollbar Generator

Style a scrollbar's width, track, thumb and hover color, then see the real WebKit result next to the real Firefox result — two genuinely different browser systems, side by side.

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CSS Text Effects Generator

Type your own text and preview real neon-glow, 3D-extrude, letterpress, outlined and gradient-fill CSS effects live, with parameters computed by real math and a copyable CSS block.

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CSV Validator

Quickly check CSV files for integrity, delimiters and column matching offline.

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Cubic Bezier Generator

Design a custom CSS cubic-bezier() timing function by dragging two control points, preview it live against a linear reference, then copy the ready value.

⭐

Curl Converter

Convert curl commands into ready-to-run Python, JavaScript fetch, Node axios, PHP and Go code — locally in your browser.

⭐

Daily Word Game — 5-Letter Word Puzzle

Guess today's secret 5-letter word in six tries. Everyone who plays on the same calendar date gets the same word, with real dictionary validation and Wordle-style color feedback.

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JSON / YAML / TOML / XML Serialization Converter

Bidirectional conversion between JSON, XML, YAML, and CSV config serialization formats fully client-side.

⭐

Data Storage Converter

Convert data storage units instantly: bits, bytes, KB, MB, GB, TB and the binary KiB, MiB, GiB, TiB — with the 1000 vs 1024 distinction made explicit.

⭐

Add or Subtract Dates

Move a calendar date forward or backward by a chosen number of days, weeks, months, or years.

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Date Difference Calculator

Calculate the exact distance between two calendar dates in days, weeks, months, and years.

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Day of the Week Calculator

Find the weekday for any date plus its ordinal day and the days remaining in that year.

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Days Until Calculator

See how many days are left until any date or holiday — Christmas, New Year, Halloween, Valentine's Day or next Friday — counted live in your browser.

⭐

Dead Pixel Test

Fill your screen with solid white, black, red, green, blue and gray to spot dead or stuck pixels — plus a flashing fixer that may revive stuck ones.

⭐

Debt Payoff Calculator

Plan how up to five debts get paid off with the snowball or avalanche strategy: debt-free date, total interest, payoff order and the savings between the two.

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Decking Calculator — Deck Boards & Joists Needed

Work out how many linear feet of decking boards and how many joists a deck needs, using real actual-vs-nominal lumber dimensions, a board expansion gap, standard 16in/24in on-center joist spacing, and a waste allowance for cuts.

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Depreciation Calculator

Generate a full straight-line or declining-balance depreciation schedule for an asset, year by year, with a chart comparing both methods' book value over time.

⭐

Dice Notation Roller

A real tabletop dice notation parser: type 3d6+2, 4d6kh3 or adv and get every individual die roll, kept/dropped dice and the total.

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Dice Roller

Roll multiple 3D dice, set each die color, and reroll only selected dice.

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Diceware Passphrase Generator — Random Word Passphrases

Generate strong, memorable passphrases built from random real words using the Diceware method — true cryptographic randomness, with the actual entropy in bits shown honestly.

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Discount Calculator

Calculate the sale price after a discount, see how much you save, and stack a second discount on top.

⭐

Dockerfile Validator

Syntax validation and best practices for writing Dockerfiles locally in the browser.

⭐

Dog Age Calculator (Dog Years to Human Years)

Convert your dog's age to human years with two published models — the AVMA/AKC size-class table and the 2019 UCSD epigenetic formula — plus a life-stage label.

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Drawing Word Generator

Deal easy-to-draw words for sketching party games: a difficulty filter, a skip counter and an optional 60-second sketch timer.

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Drywall Calculator — Sheets & Screws Needed

Add up wall and ceiling sections — by length × height or a direct area, as many rows as you need — and get the number of standard 4×8ft or 4×12ft drywall sheets to buy, plus an optional honest rule-of-thumb screw-count estimate.

⭐

Elden Ring Runes Calculator

Calculate the total Runes needed to reach your target level in Elden Ring, and estimate runs on popular farming spots.

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Electricity Cost Calculator — Appliance Running Costs

See what any appliance adds to your electricity bill: pick a device or enter watts, hours per day and your price per kWh to get energy use and cost per day, month and year.

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AES-GCM Secure Encrypted Notepad

Author, encrypt, and decrypt custom text files locally using secure AES-GCM 256-bit password-based encryption.

⭐

ENV Diff Checker

Compare two .env files (staging vs. production, before vs. after a deploy) and see exactly which keys were added, removed or changed, with secret-looking values masked automatically.

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ENV Validator

Analyze .env files for syntax correctness, open quotes and duplicate keys offline.

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EXIF Viewer — View & Remove Photo Metadata

Inspect EXIF metadata of JPEG and PNG photos — camera, date, GPS location — and download a clean copy with all metadata removed.

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20-20-20 Eye Strain Timer

A live background timer for the American Optometric Association's 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds, with a real 20-second break countdown when it's time.

⭐

Fancy Text Generator

Type once and copy your text in 14 Unicode font styles: bold, cursive, bubble, small caps, upside down, zalgo and more.

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Fantasy Name Generator

Generate fantasy names for elves, dwarves, orcs, humans, dragons and wizards from race-specific syllable tables — with gender and surname options.

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Favicon Generator

Generate a complete favicon set — PNG 16/32/48/180/192/512 plus favicon.ico — from any image, right in your browser.

⭐

Fence Calculator — Posts, Rails & Pickets from a Linear Run

Work out how many posts, rails and pickets a fence needs from its total linear run: pick a post spacing, account for gates as a real deduction from the run, and get a materials count that honestly includes the classic "N spaces need N+1 posts" fencepost problem.

⭐

AES-256 File Encryptor

Password-protect any file into a portable AES-256-GCM encrypted bundle, and decrypt it back later with the same password, entirely offline.

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Find Duplicate Lines

See which lines repeat in any list or text — with exact counts, privately in your browser.

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Firewood Cord Calculator — Stack Dimensions & Face Cord Conversion

Work out how many cords a stack of firewood is from its length, width and height — or convert 'face cords' (a.k.a. ricks) of a given log length into standardized full cords, since a face cord's size always depends on how the logs were cut.

⭐

Fraction Calculator

Add, subtract, multiply and divide fractions and mixed numbers, simplify them, and convert fraction to decimal and back — with steps.

⭐

Freelance Rate Calculator

Reverse-engineer the day rate or hourly rate you must charge as a freelancer or consultant from your target take-home income, overhead, taxes and realistic non-billable time.

⭐

Fuel Cost Calculator — Trip Cost by Distance & Consumption

Calculate how much fuel a trip needs and what it costs from distance, consumption (L/100km, km/L or MPG) and fuel price — with cost per passenger.

⭐

Gamepad Tester

Test any controller online: press buttons to light them up, watch live stick crosshairs, measure stick drift against a deadzone circle and try vibration.

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GCF & LCM Calculator

Greatest common factor and least common multiple of 2–10 numbers, with the Euclidean algorithm shown step by step and the prime factorization of every number.

⭐

Gematria Calculator

Compute the gematria of any word or phrase in Hebrew or Latin letters — six classic ciphers, entirely in your browser.

⭐

Genshin Impact XP Calculator

Calculate the Adventure Rank (AR) experience points, days, and daily commissions required to reach your target rank in Genshin Impact.

⭐

Gitignore Tester

Paste your .gitignore rules and a list of file paths to see exactly which files are ignored, by which exact rule and line, and which negation rules are silently dead because a parent directory is already ignored.

⭐

Glassmorphism Generator

Dial in a frosted-glass card — blur, tint, border highlight, corner radius and shadow — previewed floating over a genuinely animated background so blur quality is visible in motion.

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GPA Calculator — Weighted Grade Point Average

Calculate your credit-weighted GPA from letter grades on the 4.0, 5.0 or 100-point scale, with instant conversion between scales.

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Grade Calculator

Find the final exam score you need to reach your desired grade, or compute a weighted average of up to five grades.

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Guitar Chord Diagrams

Type any chord name — Cmaj7, F#m7b5, G/B, anything — and get real, computed fretboard chord-box diagrams from a brute-force voicing search, not a static lookup image.

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Guitar Scale Fingering

Map any scale onto the guitar fretboard by position: fingers 1-4, root markers, and the positions that cover the whole scale — for classical and any six-string guitar.

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Half-Life Decay Calculator

Solve the exponential decay equation N(t) = N0 x (1/2)^(t/half-life) for any substance, isotope or drug you name — enter any three of remaining amount, initial amount, elapsed time and half-life, and it solves for the fourth with the rearranged formula shown step by step.

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Hangman Game — Classic Word Guessing

Play classic Hangman in your browser: guess the hidden word one letter at a time before the stick figure is complete, with five word categories and full keyboard support.

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HAR File Waterfall Analyzer

Upload a .har file exported from your browser's DevTools to see a real request waterfall built from each request's own timing data, plus checks for missing cache headers, uncompressed responses, and render-blocking scripts.

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Cryptographic Checksum Hash Generator

Generate and compare multiple cryptographic hash checksums (MD5, SHA-1, SHA-256, SHA-512) for text and large files locally.

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Hashtag Generator

Turn any post text into ready-to-paste hashtags: keyword extraction, CamelCase tags and a platform-aware counter.

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Heart Rate Zone Calculator

Calculate your five heart rate training zones from age using the Tanaka formula, with optional Karvonen (heart rate reserve) targets from your resting pulse.

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Hebrew Date Converter

Convert any Gregorian date to the Hebrew calendar and find when its Hebrew anniversary next occurs.

⭐

HEIC to JPG Converter

Convert iPhone HEIC/HEIF photos to JPG or PNG instantly in your browser — no upload, no app, no account.

⭐

HMAC Generator & Verifier

Generate and verify HMAC message authentication codes with SHA-256, SHA-384, SHA-512, or SHA-1 using a secret key, entirely in your browser.

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House Number Numerology

Find the numerological number of your house or apartment — including letters like 12B — and read what kind of home it makes.

⭐

HTML Accessibility Auditor

Paste raw HTML and get a real WCAG accessibility audit: a hand-built DOM walker checks images, form labels, heading order and link text, plus a genuine relative-luminance contrast-ratio calculator scored against the real AA/AAA thresholds — no external library, nothing sent anywhere.

⭐

HTML Table Generator

Build an HTML table visually by clicking cells and typing — get clean, semantic table markup with a live preview, no format to paste or convert.

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HTML & URL Encoder / Decoder

Escape HTML entities and encode URL percent strings safely.

⭐

HTML Validator

Analyze HTML code for open tags, nesting correctness and markup validity offline.

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IBAN Validator

Validate an IBAN's real ISO 7064 mod-97 checksum and cross-check its total length against a bundled per-country format table — entirely offline in your browser.

⭐

Ideal Weight Calculator

Calculate your ideal body weight from height and sex with four classic formulas — Devine, Robinson, Miller and Hamwi — plus the healthy BMI range, right in your browser.

⭐

IEEE-754 Float Visualizer

See exactly how a decimal number is stored as an IEEE-754 float — sign bit, exponent bits and mantissa bits — and why numbers like 0.1 aren't stored exactly.

⭐

Image Border & Rounded Corners

Add a colored border and round the corners of any picture, with a live preview right in your browser.

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Image Color Picker

Pick any color from a photo right in your browser: a zoom loupe magnifies the pixels, one click gives you HEX, RGB and HSL codes to copy.

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Image Compressor

Reduce the size of images (PNG, JPEG, WebP) locally in the browser without losing quality.

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Image Converter

Quickly convert images between PNG, JPEG, WebP, GIF, BMP offline in the browser.

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Image Cropper

Crop images with a handy selection box locally in the browser.

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Image Diff Checker

Upload two images and see a pixel-accurate visual diff between them, with perceptual YIQ comparison and anti-aliasing-aware highlighting — 100% local in your browser.

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Image Dithering

Apply real Floyd-Steinberg, Atkinson or Bayer ordered dithering to any photo and reduce it to a 1-bit, 4-shade or reduced-RGB palette — a genuine retro/halftone look, processed locally in your browser.

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Image Palette Extractor

Extract the real color palette of any photo in your browser: median-cut quantization finds 3–12 key colors with HEX codes, CSS variables and JSON export.

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Image Resizer

Change the width and height of images in pixels or percentages locally and securely.

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Steganography Hidden Image Encoder

Hide confidential text messages inside image pixels using LSB encoding or recover data from encoded PNG files offline.

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Image to ASCII Art Converter

Turn any photo into real ASCII art in your browser: real per-cell luminance sampling maps every patch of the image to a text character, in plain monochrome or colored HTML spans.

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Image to Text Converter (OCR)

Extract text from images with OCR directly in your browser: JPG, PNG, WebP and BMP in 12 recognition languages.

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Image Upscaler

Enlarge an image 2x, 3x or 4x using real Lanczos or bicubic convolution resampling, shown honestly side by side against the browser's default bilinear scaling — classic resampling, not AI.

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Images to PDF Converter

Turn JPG, PNG, WebP or BMP images into a single PDF with page size, margins and orientation control.

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Inflation Calculator

See what a dollar amount from any year between 1913 and 2025 is worth in another year using official US CPI data, or project a future value at a custom inflation rate.

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INI Validator

Validation of INI configuration files for correct sections, keys and values offline.

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Guitar and Ukulele Tuner

Tune guitar, ukulele, bass, violin, and mandolin with live microphone pitch detection.

⭐

Insulation R-Value Calculator — Assembly R-Value vs. Climate Zone

Stack as many insulation layers as your assembly actually has — material type and thickness per layer — and add them into a total R-value, then compare that total against published US DOE climate-zone recommendations for attics, walls and floors to see a plain meets/below-recommended verdict.

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Intermittent Fasting Timer

Pick a 16:8, 18:6, 20:4, OMAD or 5:2 fasting protocol and watch a live countdown to your next eating or fasting window — a scheduling tool, not a health claim.

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Interval Ear Trainer

Hear two live-synthesized notes, name the musical interval, and let adaptive difficulty focus practice on your weakest intervals.

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Invisible Text Generator

Copy invisible characters or generate blank text of any length: zero-width space, Hangul Filler, Braille blank and more.

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Invoice Generator (PDF)

Fill in your business and client details, line items, tax rate and due date, then download a clean, correctly laid out PDF invoice — no signup and no cloud storage of your business data, unlike SaaS invoicing tools.

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JSON Diff Checker

Compare two JSON payloads by structure, not by text: see every added, removed and changed key on its own path, entirely in your browser.

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JSON Formatter

Beautifully format, validate, compress and sort JSON data locally.

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JSON Schema Validator

Validation of JSON documents against a given JSON Schema locally.

⭐

JSON to TypeScript Converter

Convert JSON into TypeScript interfaces, type aliases or a Zod schema live, with real optional-field detection across arrays.

⭐

JSON Validator

Check JSON structure and configurations for errors offline in the browser.

⭐

JWK ⇄ PEM Key Converter

Convert cryptographic keys between JWK and PEM format using the real Web Crypto API, decode algorithm/curve/size, and compute the RFC 7638 JWK thumbprint.

⭐

JWT Token Debugger

Decode, inspect and verify the signatures of JSON Web Tokens fully client-side.

⭐

Key Chord Builder

Build the diatonic chords of a selected key and label every degree with its harmonic role.

⭐

Keyboard Tester

Press any key and watch it light up on an on-screen keyboard: check every switch, count simultaneous keys and spot dead or chattering keys.

⭐

Keyword Density Checker

Live keyword density analysis: top 1-, 2- and 3-word phrases with counts and density percentages, stop-word filtering and a target keyword check.

⭐

Kubernetes Manifest Linter

Lint Kubernetes YAML manifests against cluster-hardening best practices, entirely offline in your browser.

⭐

LC Resonance Calculator

Calculate LC resonant frequency, reactance, optional Q factor, and bandwidth from inductor and capacitor values.

⭐

LED Resistor Calculator

Choose a series resistor for one or more LEDs and estimate resistor power dissipation.

⭐

Length Converter

Convert length units instantly: millimeters, centimeters, meters, kilometers, inches, feet, yards and miles.

⭐

Life Path Number Calculator

Calculate your life path number from your date of birth and read what it says about you — privately in your browser.

⭐

Line Counter

Count lines in any text live as you type: total, non-empty and blank lines, plus longest and average line length.

⭐

Loan Calculator

Calculate the monthly payment, total cost and total interest of any loan, with a first-year amortization breakdown.

⭐

Long Division Calculator

Divide two whole numbers with the full long-division bracket drawn step by step: every multiply, subtract and bring-down, quotient with remainder, decimal expansion and mixed number.

⭐

Lorem Ipsum Generator

Generate classic lorem ipsum placeholder text as paragraphs, sentences, or words right in your browser.

⭐

Lucky Numbers Calculator

Get your personal set of lucky numbers derived from your birth date and, optionally, your name — with every source explained.

⭐

Macro Calculator (Protein, Carbs & Fat)

Calculate your daily protein, carbs and fat in grams from your calorie needs, goal and diet style — Mifflin-St Jeor based, right in your browser.

⭐

Magic 8-Ball

Ask a yes-or-no question and shake the classic Magic 8-Ball with its twenty original answers.

⭐

Magic Bytes & Binary Header Doctor

Inspect file magic signatures, view raw hex/ASCII headers, and repair corrupted binary file headers client-side.

⭐

Margin Calculator

Calculate revenue, profit, margin and markup from a cost plus any one of selling price, margin percent or markup percent — with both formulas shown.

⭐

Markdown Converter

Instant two-way conversion between Markdown markup and plain HTML.

⭐

Markdown Table Generator

Build a Markdown table visually: click a cell and type, add rows and columns, set per-column alignment, and copy the ready GFM table.

⭐

Math Worksheet Generator

Generate a printable A4 arithmetic worksheet for kids — addition, subtraction, multiplication, division and number-house problems, plus a matching answer key.

⭐

Matrix Calculator

Add, subtract, multiply and transpose 2×2 or 3×3 matrices, plus find the determinant and inverse with the full cofactor-expansion trace — minors, signed cofactors, the adjugate and every step shown as exact fractions.

⭐

Meat Cooking Time Calculator

Estimate roasting time for turkey, chicken, beef, pork, ham and lamb from weight and oven temperature, with USDA safe internal temperatures and rest times.

⭐

Meeting Time Planner

Compare one proposed meeting time across an organizer and two attendee time zones.

⭐

Meme Generator

Free online meme maker: caption your own images with classic top and bottom text and export PNG or JPEG.

⭐

Meta Robots & Canonical Builder

Build a valid meta robots tag and canonical link, or paste existing <head> HTML to audit it for real indexing conflicts like duplicate canonicals and contradictory directives.

⭐

Metronome

Professional online metronome with selection of tempo and sound accents for rehearsals.

⭐

Mic Test

Test your microphone online: live level meter, waveform and a record-and-playback check — fully in your browser.

⭐

Military Time Converter

Convert military (24-hour) time to regular 12-hour AM/PM time and back, with a full 24-row reference chart.

⭐

Minecraft Circle Generator

Generate pixel-perfect Minecraft circles and ellipses with thin, thick, or filled outlines and an exact block count.

⭐

Minecraft XP Calculator

Calculate the exact experience points, levels, and farm activities needed to reach your target level in Minecraft.

⭐

Random Fake Data & Mock API Generator

Produce realistic mock datasets including names, emails, addresses, companies, and credit cards fully offline.

⭐

Moon Phase Calculator

See the moon phase for any date: a drawn moon disc, illumination percentage, lunar age and the traditional meaning of the phase.

⭐

Morse Code & Cipher Playbook

Translate to Morse code with audio player and decode classic Caesar, Rot13 and Vigenere ciphers.

⭐

Mortgage Calculator

Calculate your monthly mortgage payment from the home price, down payment, rate and term — with property tax and insurance included.

⭐

Mouse Sensitivity Converter

Convert mouse sensitivity settings between popular games, calculate eDPI, and find physical cm/360 rotation distance.

⭐

Mouse Tester

Test every mouse button online: left, right, middle and side buttons light up on a mouse graphic, with press counters, a scroll check and a double-click detector.

⭐

Mulch, Topsoil, Compost & Gravel Calculator

Calculate how much mulch, topsoil, compost or gravel you need from area and depth — cubic yards, cubic feet, estimated weight and bags to buy.

⭐

Name Numerology Calculator

Turn a name into its numerology: expression, soul urge and personality numbers with interpretations — in your browser.

⭐

NATO Phonetic Alphabet Converter

Spell any text using the NATO/ICAO phonetic alphabet (Alfa, Bravo, Charlie...) live as you type, plus a full A-Z and digit reference table.

⭐

Net Present Value (NPV) Calculator

Discount a series of uneven cash flows back to today's value at a chosen rate, with a per-period discounted-value breakdown and a sensitivity table at nearby rates.

⭐

Nether Portal Calculator

Convert coordinates between the Overworld and the Nether (÷8 / ×8) and link your Minecraft portals precisely.

⭐

Never Have I Ever Generator

Deal family-friendly “Never have I ever” statements from friends, funny and travel decks — 90 hand-written cards with no repeats.

⭐

Notepad Calculator

Write notes along with mathematical expressions - the tool will calculate everything line by line.

⭐

Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal — arbitrary size, entirely in your browser.

⭐

Add Line Numbers

Prepend sequential numbers to every line of a list or text instantly and privately in your browser.

⭐

Numbers to Words

Converting numbers and monetary amounts into text with correct cases and currencies.

⭐

Office Table Converter

Convert data between CSV, TSV, HTML, Markdown and JSON without uploading to the server.

⭐

OG Image Generator — Social Share Image Maker

Compose a 1200×630 Open Graph social-share image with a title, subtitle, background and logo, rendered live on a real canvas — then preview how it looks framed inside Twitter/X, Facebook, LinkedIn and Discord link cards before you download the clean PNG.

⭐

OG & Twitter Card Generator — Meta Tag Builder, Auditor & Preview

Build ready-to-paste Open Graph and Twitter Card <meta> tags from a form, or paste an existing <head> to audit it for missing tags, title/description length and twitter:card validity — then preview both in genuinely re-styled Twitter/X, Facebook, LinkedIn and Discord link-card mockups.

⭐

Ohm's Law Calculator

Find voltage, current, resistance, and power from any two known electrical values.

⭐

One Rep Max (1RM) Calculator

Estimate your one rep max from any set of 2–12 reps using four proven formulas, and get your training percentages from 50% to 95%.

⭐

Op-Amp Gain Calculator

Calculate inverting and non-inverting op-amp gain, dB gain, and expected output voltage.

⭐

Ovulation Calculator

Estimate your ovulation date, fertile days, and next period from your last period and cycle length.

⭐

Paint Calculator — How Much Paint for a Room or Wall

Work out how many liters of paint a room, wall, ceiling or facade needs: wall area from dimensions or direct input, minus doors and windows, times coats — with can sizes to buy.

⭐

Password Crack Time Estimator

Type a password and see a transparent entropy calculation plus honest crack-time estimates across several clearly-labeled attack scenarios — computed entirely in your browser, never a mystery strength score.

⭐

Password Hasher & Key Derivator

Hash passwords and derive cryptographic keys client-side using PBKDF2 and Scrypt KDF algorithms.

⭐

Payback Period Calculator

Find out how many years or periods it takes for an investment's cash flows to repay its initial cost, with simple and discounted payback compared side by side over a full cumulative cash-flow table.

⭐

PCB Trace Width Calculator

Estimate PCB trace width from current, temperature rise, copper thickness, layer location, and trace length.

⭐

PDF Compressor

Reduce the size of PDF files by optimizing images and fonts locally.

⭐

PDF Form Filler

Open a fillable PDF, type your answers into a real form built from its own fields, and download a completed copy — entirely in your browser.

⭐

PDF Header & Footer / Page Number Stamper

Add page numbers ("Page X of Y") and/or custom header text to every page of a PDF, with adjustable position and a start-at offset, entirely offline.

⭐

Merge PDF Files

Combine several PDF files into one document in your chosen order, entirely in the browser.

⭐

PDF Page Organizer

See every page of a PDF as a thumbnail, then drag to reorder, delete with undo and rotate single pages — and save the result locally in the browser.

⭐

PDF Redactor

Draw black boxes over sensitive parts of a PDF that permanently destroy the text and image data underneath — real redaction, not a cosmetic overlay.

⭐

Rotate PDF Pages

Rotate PDF pages by 90, 180 or 270 degrees — all pages or a chosen range — locally in the browser.

⭐

Split PDF Online

Split a PDF into single pages or extract a page range into a new document, right in the browser.

⭐

PDF to JPG Converter

Render every page of a PDF to a JPG or PNG image in the browser, with adjustable resolution and quality.

⭐

PDF to Markdown Converter

Extract a PDF's text as structured Markdown: real heading detection from font size, list detection from bullets and indent — not one flat wall of text.

⭐

PDF to Text Converter

Extract the plain text from a PDF's text layer in the browser, page by page, ready to copy or download.

⭐

PDF Watermark Stamper

Stamp a text watermark — CONFIDENTIAL, DRAFT or your own wording — across every page of a PDF, diagonal, tiled or in a corner, entirely offline.

⭐

Percentage Calculator

Calculate percentages in every direction: X% of a number, what percent X is of Y, percentage change, increase and decrease.

⭐

Permutations & Combinations Calculator (nPr, nCr)

Compute nPr (permutations) and nCr (combinations) from the same n and r, with the real factorial-cancellation working shown step by step in exact BigInt arithmetic.

⭐

Personal Year Number

Find your personal year, month and day numbers for any date and read the theme of your current cycle.

⭐

Pet Name Generator

Pick a species and a style and get eight pet name ideas per click — with click-to-copy and a favorites shortlist.

⭐

Phone Number Numerology

Check the numerology of a phone number: its core number, dominant digits and what they are said to attract.

⭐

Photo Filters

Apply grayscale, sepia, invert and pencil sketch effects to photos with an intensity slider — locally in your browser.

⭐

Piano Scale Fingering Chart

See the standard fingering for any major or minor piano scale on an interactive keyboard — right hand, left hand, one or two octaves, with thumb-under crossings marked.

⭐

Pixel Art Converter

Turn any photo into genuine retro pixel art: a real box-filter downscale plus nearest-color quantization onto a real Game Boy, CGA, PICO-8 or NES-inspired palette, with optional Floyd-Steinberg dithering.

⭐

Poker Odds Calculator — Texas Hold'em Equity Math

A combinatorics tool that computes exact win/tie/lose probabilities for Texas Hold'em hands using a real 7-card hand evaluator and full board enumeration or Monte Carlo simulation.

⭐

Pomodoro Timer

Stay focused with timed work sessions and automatic short and long breaks, complete with a gentle beep and a live countdown in the tab title.

⭐

Position Size Calculator

Enter your account size, risk per trade, entry price and stop-loss to get the exact position size that keeps your risk within your rule, plus an R-multiple profit table.

⭐

Preferred RC Filter Designer

Find practical E12, E24, or E96 resistor and capacitor pairs for a target RC filter cutoff.

⭐

Pregnancy Due Date Calculator

Estimate your due date from the last period, conception date, or IVF transfer, with week-by-week milestones.

⭐

Pressure Converter

Convert pressure units instantly: pascals, kilopascals, megapascals, bar, psi, atmospheres and millimeters of mercury.

⭐

Price per Unit Calculator

Compare 2–4 products by their real unit price: prices are normalized per 100 g, per kg, per litre, per ounce or per item, the cheapest one is highlighted and the rest show how many percent more they cost.

⭐

Primality Checker

Test whether a number is prime and see exactly why: real trial division up to √n for small and medium numbers, and a genuine Miller–Rabin walkthrough for cryptography-sized numbers.

⭐

Prime Factorization Tree

Factor any integer into its prime factors and see it rendered as the classic branching factor tree taught in school, plus the compact exponent form (360 = 2³ × 3² × 5).

⭐

Projectile Motion Calculator

Enter a launch speed and angle to get the real range, max height and time of flight of a projectile — the launch velocity is decomposed into vx and vy, every kinematics substitution is shown, and an actual trajectory chart is plotted from those same equations.

⭐

Protein Intake Calculator (Daily Range)

Get your daily protein target as an honest low-high range in grams, based on your body weight and activity goal — plus food equivalents, right in your browser.

⭐

PX to REM Converter

Convert px to rem, rem to px and px to em at any base font size, with a copy-ready CSS line and a live reference table.

⭐

Pythagoras Square (Psychomatrix)

Build your Pythagoras square from your date of birth: a 3×3 psychomatrix with an interpretation for every cell.

⭐

Pythagorean Theorem Calculator

Solve a² + b² = c² step by step: find the hypotenuse from two legs, find a missing leg, or test whether three sides form a right triangle — with exact simplified radicals like 5√2, a scaled diagram, area and perimeter.

⭐

QR Code Generator

Create custom QR codes from links, texts and Wi-Fi networks locally in the browser.

⭐

QR Code Scanner

Scan QR codes from files or your webcam instantly and privately in your browser.

⭐

Quadratic Equation Solver

Solve ax² + bx + c = 0 with the full quadratic formula worked out step by step: exact roots like (3 ± √5)/2 or −1 ± 2i, the discriminant, the vertex and the factored form.

⭐

Race Training Plan Generator

Build a safe week-by-week mileage progression for your next race from your current mileage, race distance and weeks to go, using the published 10% rule plus a step-back taper.

⭐

Random Name Picker

Pick random winners from a pasted list of names — remove winners after each draw, draw several at once, and go fullscreen for classroom or raffle displays.

⭐

Random Word Generator

Generate random English words filtered by part of speech, starting letter, and length — nouns, verbs, and adjectives from a curated 1,180-word list.

⭐

Ratio Calculator

Simplify ratios, solve proportions A : B = C : x, scale ratios by any factor and convert them to fractions, decimals and percentages — with every step shown.

⭐

RC High-Pass Calculator

Calculate RC high-pass cutoff, impedance, gain, phase, and response at a test frequency.

⭐

RC Low-Pass Calculator

Calculate RC low-pass cutoff, impedance, gain, phase, and response at a test frequency.

⭐

Readability Checker

Score your text live with six classic readability formulas: Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau and ARI.

⭐

Realtime Spectrum Analyzer

Realtime Spectrum Analyzer shows the frequency content of sound directly in the browser without uploading it to a server.

⭐

Receipt Generator (PDF)

Generate a simple sales or payment receipt as a downloadable PDF — business name, itemized list, tax, total and payment method — with a compact thermal-printer layout option, assembled entirely in your browser.

⭐

Recipe Scaler

Paste an ingredient list, set the original and the target number of servings, and get every quantity rescaled with kitchen-friendly rounding.

⭐

Refresh Rate Test

Measure the refresh rate your browser really renders: a live Hz readout from frame timestamps, a frame-time graph, a skipped-frame counter and a UFO-style smoothness test.

⭐

Regex Tester Online

Debug JavaScript regular expressions live: highlighted matches, capture groups, flags, and replacement preview.

⭐

Remove Duplicate Lines

Delete repeated lines from any list or text instantly and privately in your browser.

⭐

Remove Line Breaks

Clean unwanted line breaks and extra whitespace from pasted text instantly and privately in your browser.

⭐

Rent Affordability Calculator

See how much rent you can afford under three real published affordability rules side by side — the 30% rule, the 50/30/20 budget, and the landlord's 40x-rent screening rule — plus a reverse mode that turns a target rent into a required income.

⭐

Replace in Text

Convenient replacement of text or regular expressions (Regex) with case saving locally in the browser.

⭐

Resume Builder

Fill in your contact details, summary, experience, education and skills to generate a clean, single-column, ATS-friendly resume PDF — entirely in your browser.

⭐

Reverse Text

Flip text backwards instantly: reverse characters, words, or lines right in your browser.

⭐

Rhyme Finder

Find perfect and near/slant rhymes for any English word from a curated ~1,500-word phonetic dataset, organized by real matching sounds, not spelling.

⭐

Rhythm Sight-Reading Trainer

Practice reading and tapping random rhythms with real, measured timing-accuracy feedback.

⭐

Ring Size Converter

Convert ring sizes between the US, UK, EU/ISO and Japanese systems, or start from a measured diameter or circumference in millimetres.

⭐

RLC Q Calculator

Calculate resonance, Q factor, and bandwidth for series or parallel RLC circuits.

⭐

Robots.txt Tester

Paste a robots.txt file, pick a crawler — including GPTBot, ClaudeBot and Google-Extended — and instantly see whether it can fetch a given URL path, with the exact rule and line number that decided it.

⭐

ROI Calculator

Calculate the return on any investment: total ROI %, profit, annualized CAGR and the doubling time by the rule of 72 next to the exact answer.

⭐

Roman Numerals Converter

Convert numbers 1–3999 to Roman numerals and back, with a place-by-place breakdown and strict validation.

⭐

Roofing Shingle Calculator — Squares & Bundles from Pitch

Add up your roof's footprint sections, enter the pitch as rise per 12 inches of run, and get the real sloped roof area, plus the squares and bundles of shingles to buy after waste — using the actual trigonometric pitch factor roofers use, not a flat area estimate.

⭐

Rotate & Flip Image

Rotate pictures by 90° or 180° and flip them horizontally or vertically, all locally in your browser.

⭐

Rounding Calculator

Round any number to any place value — from millions to ten-thousandths — with exact digit-by-digit math and a clear explanation of the result.

⭐

Rune of the Day

Draw one of the 24 Elder Futhark runes as your rune of the day, with its glyph, name and meaning.

⭐

Running Pace Calculator

Calculate your running pace per km and per mile, finish time and km splits, or predict race times with the Riegel formula — right in your browser.

⭐

Salary Converter

Convert any pay amount between hourly, daily, weekly, biweekly, monthly and annual — based on your real hours per week and weeks per year.

⭐

Savings Goal Calculator

Plan a savings goal two ways: find the monthly deposit that reaches a target amount by a date, or how long a given monthly deposit will take, with interest.

⭐

Schema Markup Generator (JSON-LD)

Build valid JSON-LD structured data for FAQ, Article, Local Business, Product, Breadcrumb, Organization and Event pages — live, private, ready to paste.

⭐

Screen Resolution Checker

See your screen resolution, browser viewport size, device pixel ratio, color depth and orientation — updated live as you resize.

⭐

Find in Text

Quickly search text using keywords or regular expressions (Regex) right in your browser.

⭐

Secret Santa Generator

Draw fair Secret Santa gift assignments with optional exclusion pairs, then reveal them one at a time by passing the device around — no email, no server.

⭐

Developer Secrets & Token Generator

Bulk generate cryptographically secure API keys, salts, tokens, and decode precise millisecond timestamps from UUIDv7.

⭐

Security Headers Analyzer

Paste raw HTTP response headers from curl -I or DevTools' Network tab and get a graded security audit — a real Content-Security-Policy grammar parser plus HSTS, X-Frame-Options, cookie flags and more, entirely offline.

⭐

SERP Snippet Preview

See how your title tag and meta description will look in Google search results — live desktop and mobile snippet preview with character and pixel counters.

⭐

Shoe Size Converter

Convert shoe sizes between US, UK, EU, JP and foot length in cm for men, women and kids — with the full chart row for every match.

⭐

Sig Fig Calculator

Count the significant figures in any number with every digit classified by rule, or round a number to 1–15 significant figures with exact string-based math.

⭐

Signature Generator

Draw or type your signature online and download it as a transparent or white-background PNG — free, right in your browser.

⭐

Remove Silence from Audio

Automatically find and cut silence and long pauses from your audio recordings.

⭐

Sitemap.xml Validator — Real Protocol Compliance Checker

Paste or upload a sitemap.xml (or sitemap index) and validate it against the real sitemaps.org protocol: root element and namespace, absolute <loc> URLs, the documented 50,000-URL / 50MB limits, <lastmod>, <priority>, <changefreq> — plus a freshness histogram and duplicate-URL detection.

⭐

Sleep Calculator — Sleep Cycle Bedtime & Wake-up Times

Find the best time to go to bed or wake up based on 90-minute sleep cycles, with age-based sleep recommendations — right in your browser.

⭐

Slope Calculator

Find the slope between two points as an exact fraction, plus the y-intercept, slope-intercept and point-slope forms, distance with a simplified radical, midpoint and angle of incline — with steps.

⭐

Sort Lines

Sort the lines of any list or text alphabetically, naturally, by length, or shuffle them — privately in your browser.

⭐

Speaker Test

Test your speakers online: left / right channel tones, a 20–200 Hz bass sweep and pink noise — all generated in your browser.

⭐

Speed Converter

Convert speed units instantly: meters per second, km/h, mph, knots and feet per second.

⭐

SQL Formatter

Format and beautify SQL queries or minify them to one line — entirely in your browser.

⭐

SRI Hash Generator

Generate a Subresource Integrity hash for any JS or CSS file and get a ready-to-paste script or link tag.

⭐

Stair Calculator — Risers, Tread Depth & Blondel Comfort Check

Plan a staircase from total floor-to-floor rise: get the number of risers, the exact riser height, a tread depth from the real Blondel comfort formula (2 x riser + tread), and whether the total run fits your available space.

⭐

Standard Deviation Calculator

Paste your numbers and get the sample or population standard deviation, variance, mean, SEM and CV% — with the squared deviations shown step by step.

⭐

Startup Cost Calculator

Add your one-time and monthly recurring costs, set a runway in months and a contingency buffer, and see the total capital you need to launch and survive.

⭐

Step Sequencer

Program a 16-step drum beat with kick, snare, hi-hat, and clap, then export it as a real WAV file.

⭐

Steps to KM Calculator — Steps, Distance, Miles & Calories

Convert steps to kilometers and miles (or find out how many steps a distance takes), using your real stride length or one estimated from your height, plus an optional walking calorie estimate.

⭐

Stopwatch

Time yourself to the millisecond by recording laps, locally in your browser.

⭐

String Escaper — JSON, JS, SQL & Regex

Escape or unescape strings for JSON, JavaScript/TypeScript, SQL and regex — live, entirely in your browser.

⭐

Guitar & Bass String Tension Calculator

Calculate the real pulling tension of a guitar or bass string in lbs, kg, and Newtons from its gauge, your scale length, and the target note.

⭐

Subnet Calculator

Calculate the network address, broadcast, subnet and wildcard masks, host range and usable host count for any IPv4 address and CIDR prefix.

⭐

Subtitle Converter

Convert subtitles between SRT and VTT, shift their timing by milliseconds or seconds, and renumber cues — privately in your browser.

⭐

Sudoku Generator

Generate a fresh, playable Sudoku puzzle with a real backtracking solver that verifies every puzzle has exactly one solution.

⭐

SVG to PNG Converter

Rasterize any SVG file into a crisp PNG at an exact target resolution, with a transparent or solid background and one-click 1x/2x/3x batch export.

⭐

Tarot Card of the Day — Free Online Tarot Reading

Draw one card from a fully illustrated 78-card tarot deck for an honest online tarot reading — upright or reversed, with a real meaning to reflect on, drawn locally with no account and no tracking.

⭐

Tarot Three-Card Spread — Free Online Past/Present/Future Reading

Deal a past-present-future tarot spread from a fully illustrated 78-card deck online — three distinct cards, upright or reversed, each with a real meaning, drawn locally with no account needed.

⭐

Random Team Generator

Paste a list of names and split it into fair random teams by team count or group size.

⭐

Temperature Converter

Convert temperatures between Celsius, Fahrenheit and Kelvin instantly with exact formulas.

⭐

Test Card Number Generator (Luhn-Valid, Sandbox Only)

Generate fake, Luhn-checksum-valid test card numbers from publicly documented sandbox BIN ranges (Visa, Mastercard, Amex, Discover) for QA and checkout-flow testing. Not real cards.

⭐

Text Cleaner

Strip HTML tags, smart quotes, weird dashes, emojis and invisible characters from any text — with per-category counters, privately in your browser.

⭐

Text Diff

Compare two texts side by side, line to line, and see every added and removed line highlighted, privately in your browser.

⭐

Text Similarity Checker

Compare two texts with real n-gram Jaccard similarity and a word-level LCS overlap score, with the matching passages highlighted side by side.

⭐

Text Splitter & Joiner

Split delimiter-separated text into lines or join lines back into one string, privately in your browser.

⭐

Text to Handwriting Converter

Turn typed text into a realistic handwritten note on lined notebook paper, rendered locally in your browser.

⭐

Text to Speech

Speak your written text using natural browser voices and save the audio.

⭐

Tile Calculator — How Many Tiles You Need

Work out how many tiles a floor, wall or laminate installation needs: enter a room's dimensions or its area directly, pick a common tile size or a custom one, add a waste allowance for cuts, and get a shopping list in tiles and boxes.

⭐

Time Duration Calculator

Hours and minutes between two clock times — overnight included — plus adding or subtracting hh:mm durations.

⭐

Time Unit Converter

Convert time units instantly: milliseconds, seconds, minutes, hours, days, weeks, average months and years, with a live hh:mm:ss readout.

⭐

Time Zone Converter

Convert a local date and time between any two IANA time zones with daylight-saving rules applied.

⭐

Tip Calculator

Calculate the tip and total for any bill, and split both evenly between any number of people.

⭐

Tire Size Calculator — Diameter & Speedometer Error Comparison

Parse metric (225/45R17) or flotation (33x12.5R15) tire codes, get sidewall height, overall diameter, circumference and revolutions per mile/km, and compare two sizes with the resulting speedometer error.

⭐

Title Capitalization Tool (AP, APA, Chicago, MLA)

Capitalize headlines by real style-guide rules — AP, APA, Chicago and MLA — with correct handling of articles, prepositions, hyphens and colons.

⭐

Table of Contents Generator

Paste Markdown or HTML and get a nested, clickable table of contents with real GitHub-style collision-safe anchor slugs, plus the original content with heading IDs injected.

⭐

TOML Validator

Check the syntax and structure of TOML configuration files locally and securely.

⭐

Tone Generator

Generate a clean audio tone of a given frequency and waveform locally in the browser.

⭐

TOTP Generator — Live 2FA Authenticator Code

Paste a Base32 TOTP secret and watch the real, live 6-digit authenticator code rotate every 30 seconds — entirely offline in your browser.

⭐

Triangle Calculator

Solve any triangle from three known values — SSS, SAS, ASA, AAS or SSA — and get every side, every angle, the area, the perimeter and the heights, with the law of sines and cosines steps written out and a scaled diagram.

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Truth or Dare Generator

Family-friendly truth or dare generator with kids, party and couples decks — 90 hand-written cards that never repeat until the deck runs out.

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TSV Validator

Validate TSV (Tab Separated Value) files for integrity and structure offline.

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Tweet Thread Splitter

Paste a long post and split it into a real X/Twitter thread using the actual weighted character-counting rules — every URL counts as a fixed 23 characters and astral-plane emoji count correctly — with smart paragraph/sentence/word boundaries and thread numbering that reserves its own space.

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Typing Speed Test — Free WPM Test

Measure your typing speed in WPM with live word highlighting, accuracy percentage, and error count.

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Ukulele Chord Diagrams

Type any chord name and see every playable ukulele chord shape in standard GCEA tuning — a real voicing search, not a static lookup chart, with every match you can page through.

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Unix Timestamp Converter

Convert local date and time to Unix seconds or milliseconds and decode timestamps back to readable time.

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URL Parser & Query Inspector

Deconstruct complex URLs, manage deep queries, and decode URL parameters cleanly fully client-side.

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User Agent Parser

Paste any user-agent string — from a server log, a support ticket, or curiosity — and decode its browser, OS, engine and device type instantly, including known bots like Googlebot.

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Username Generator

Generate unique aesthetic, gamer, cute or cool usernames from curated word pairs — with separators, numbers, leetspeak and platform length caps.

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UTM Link Builder

Build campaign URLs with utm_source, utm_medium and utm_campaign tags — live output, validation and clean encoding in your browser.

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VAT Calculator

Add VAT to a net price or extract it from a gross price at any rate — net, VAT amount and gross in one click.

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vCard Generator (VCF)

Create a vCard 3.0 contact file (.vcf) with a live preview and a QR code that adds the contact to any phone on scan — free, in your browser.

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Vector Calculator

Compute the dot product, cross product, magnitude, unit vector and angle between two 2D or 3D vectors — with the term-by-term dot product expansion, the i/j/k determinant mnemonic, and exact simplified radicals like 5√2 shown at every step.

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Video Frame Extractor

Extract still frames from a video at a fixed interval or a specific list of timestamps and download each one, right in your browser.

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Video to GIF Converter

Turn MP4 or WebM clips into animated GIFs right in your browser — pick the segment, FPS and width, no upload needed.

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Video to MP3 Converter — Extract Audio from Video

Extract the audio track from MP4 or WebM video and save it as MP3 or WAV — entirely in your browser, no upload.

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Video Trimmer — Cut Video Online

Trim a video to the exact segment you need directly in your browser — sliders with frame preview, no upload, no watermark.

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VO2 Max Calculator

Estimate your VO2 max (cardiorespiratory fitness) from the Cooper 12-minute run or the Rockport 1-mile walk test, with a fitness-level category by age and sex.

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Voice Recorder

Record sound from the microphone directly in the browser with instant download.

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Voltage Divider Calculator

Calculate ideal and loaded voltage divider output, current, resistor power, and effective resistance.

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Volume Converter

Convert volume units instantly: milliliters, liters, teaspoons, tablespoons, fluid ounces, cups, pints, quarts, gallons and cubic meters.

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Waist-to-Hip Ratio Calculator

Calculate your Waist-to-Hip Ratio (WHR) from waist and hip circumference, with the WHO 2008 risk category and a separate NIH/ATP-III waist-circumference cross-check.

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Wallpaper Calculator — Rolls Needed, Pattern-Repeat Waste Included

Work out how many wallpaper rolls a room needs: enter the wall length (or room length × width) and height, pick a roll size, and — unlike a flat waste percentage — enter the pattern repeat so the calculator can show the real material lost to matching a large repeat.

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Fast Client-Side Utilities