Day of the Week Calculator
Find what day of the week any date falls on.
Which weekday was that
Knowing the day of the week for a date — past or future — is useful for history, planning and curiosity. This finds the weekday for any date you enter, from your birth date to a date centuries away.
Enter a date to find its day of the week.
The pattern behind the days
Working out the weekday of a distant date by hand is genuinely hard, because it depends on the total days elapsed, including all the leap years in between, which is why methods for doing it in your head are considered impressive party tricks. The calculation handles it instantly and correctly. There is a neat fact worth knowing: because the pattern of days and leap years repeats on a four-hundred-year cycle, the calendar itself repeats exactly every four hundred years, so any date has a fixed long-term pattern of weekdays. Finding the day of the week is fun for discovering what day you were born, satisfying for settling which weekday a future event lands on, and occasionally practical for historical dating.
Questions & answers
Why is finding a distant weekday hard by hand?
Because it depends on the total days elapsed, including every leap year in between, which is why mental methods for it are considered impressive tricks.
Does the calendar repeat?
Yes — because leap years follow a four-hundred-year cycle, the whole calendar of weekdays repeats exactly every four hundred years.
Is anything uploaded?
No. The calculation happens in your browser.