Day of the Week Calculator
Name the weekday of a calendar date and give its day-of-year number and how many days remain after it.
Processed entirely in your browser — nothing you enter here is ever uploaded.
Result
About this tool
The control is a date input. The page parses year-month-day into a UTC date and rejects a value that is not a real calendar day. There is no clock time. The weekday line uses Intl with the weekday set to long and the time zone set to UTC, in the language of the page, so an English page spells Thursday rather than a number. The detail line is the day of the year and the days remaining after that day.
Day of year is the number of UTC midnights from 1 January of that year up to the date, plus 1. 1 January is day 1. 29 February 2024 is day 60, because 2024 is a leap year and February 29 is the 60th day. The length of the year is the day-of-year of 31 December, which is 366 in 2024 and 365 in 2025. Days remaining are that length minus the day-of-year, so 29 February 2024 reports 306 days remaining. The remaining count does not include the day itself. 31 December reports 0 days remaining. 1 January 2025 is a Wednesday and is day 1 of a 365-day year, so 364 days remain.
The leap day is the case worth checking by hand. 1 March 2024 is day 61. 1 March 2025 is day 60, because 2025 has no 29 February and the days after February shift back by one. The page does not print a week number. That is the week-number tool, which uses ISO weeks. This page does not print the number of days until another date you choose. It only measures within the year of the date you picked. A date in December still uses 31 December of that same year as the end.
The result updates as you change the date. Nothing is stored and nothing is sent. The formatter can name the weekday in whatever language the page is, but the numbers are the same in every language because they come from the UTC day count. The tool does not apply a Julian calendar, and it does not accept a year-day number and turn it back into a date. If the input cannot be parsed, the result line is the invalid-date string from the page's strings. 29 February 2024 is a Thursday, day 60 of 366, with 306 days remaining after it. 1 March 2025 is a Saturday and day 60 of 365, because that year has no leap day and the count after February shifts back by one. This page still does not print an ISO week number for either date.
Example. 29 February 2024 is a Thursday, day 60 of 366, with 306 days remaining. 1 March 2025 is day 60, because 2025 is not a leap year. 31 December reports 0 days remaining.
Limit. The date is a UTC calendar day with no time of day. Days remaining do not include the selected day. Week numbers are not computed on this page.
Frequently asked questions
What day of the year is 29 February 2024?
Day 60. 2024 has 366 days, so the days remaining after 29 February are 366 − 60 = 306. The weekday line on an English page is Thursday. 1 March 2024 is day 61. 1 March 2025 is day 60, because that year has no 29 February.
Does days remaining include today?
No. It is the day-of-year of 31 December minus the day-of-year of the date you picked. 31 December itself is 0. 1 January is the length of the year minus 1, so 364 in a common year and 365 in a leap year.
Is the weekday affected by my time zone?
The date is parsed as a UTC calendar day and the weekday is formatted in UTC. There is no clock time to shift across a zone boundary. The name of the weekday follows the page language. The numbers do not.
Can I get the ISO week number here?
No. This page prints the weekday, the day of the year, and the days left in that year. The week number and the Monday-to-Sunday span are on the week-number page.