Find what weekday any date falls on — past or future — plus the day of year and ISO week.
Enter the date
Works for any date, past or future. The result also includes the ISO week and day of year.
Precise calendar calculations. Everything is computed instantly in your browser, no account, no data sent. Leap years and Gregorian calendar rules are handled.
The weekday is computed from the number of days elapsed up to the chosen date, per the Gregorian calendar, accounting for leap years:
15 June 1990 was a Friday. 25 December 2026 will be a Friday.
Enter the date (past or future) and instantly get the weekday: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday or Sunday.
Enter your birth date and the calculator tells you the weekday. For example, 15 June 1990 was a Friday.
Enter 25 December of the desired year. The calculator uses the Gregorian calendar, so the result is valid for any year.
From the number of days elapsed since a reference date, using Gregorian calendar rules and leap years. The result is exact for any date.
It works the same for the future: enter a date years ahead and get the matching weekday.
In the UK and the ISO standard, the week starts on Monday. The calculator names the exact day regardless of the start convention.
Yes. Leap years (with 29 February) are taken into account, so the weekday is correct even for dates after 29 February.
Planning events, checking days off, anniversaries, contracts with deadlines on a specific day, and simple curiosity.