Day of the Week

What day of the week is any date?

Enter any date — past or future — and the day of the week calculator tells you which weekday it falls on. It also shows the day of the year, the ISO week number, whether it’s a weekend, and how long ago or how far ahead the date is from today.

It’s handy for finding the weekday you were born, checking which day a future deadline or event lands on, planning around weekends, or settling a “what day was it?” question. Every result uses the real Gregorian calendar, so leap years and month lengths are always correct.

The trick behind weekdays

Working out a weekday by hand relies on the Doomsday rule or similar mental algorithms, but they’re fiddly and easy to slip up on across century boundaries. Letting the calendar do it is instant and exact for any year. To learn the story behind your own birth day, see our guide on what day of the week you were born on.

Related tools

To measure the gap to that date in days, use the date difference calculator; to jump a number of days forward or back, the date ± days calculator; and to count only working days, the working days calculator.