Time Unit Converter

How many hours is 90 minutes? How many seconds in a week? How many hours are 30 days? This time unit converter answers as you type, covering milliseconds, seconds, minutes, hours, days, weeks, months and years in one place, with a swap button and a common-values table under the result.

The everyday factors are exact: 1 second = 1000 ms, 1 minute = 60 s, 1 hour = 3600 s, 1 day = 86400 s and 1 week = 604800 s. Months and years have no single exact length, so the converter is honest about it: the month is the Gregorian calendar average of 30.44 days (2629746 s) and the year is the matching Gregorian average of 365.2425 days (31556952 s — exactly 12 average months). Both are labeled as averages in the unit list, so you always know you are looking at a calendar mean rather than a specific month or year.

A composite hh:mm:ss line under the result shows the entered duration as a clock-style reading — type 5400 seconds and see 01:30:00 next to the converted value. Both fields are live and two-way: enter a value in either one and the other updates instantly, rounded only for display so you never see floating-point noise.

Everything runs locally in your browser — no server call, no account, nothing to install, and the page keeps working offline once loaded. It is a practical companion for timesheets and billing, media and video timing, workout and interval planning, server timeouts and any spec sheet that mixes seconds, minutes, hours and days.