Day of the Week Calculator
What day of the week was any date.
Day of week
Monday
Monday, May 25, 2026
Day of year
145 of 365
Week of year
22
That's today
Today
About
Pick any date and see the day of the week. Useful for birth days, anniversary planning, or settling arguments about which day of the week 9/11 was.
How to use
- Pick any date.
- See the day of the week.
FAQ
Does it work for old dates?+
Yes, back to 1582 (start of the Gregorian calendar). For Julian calendar dates before 1582 the result follows Gregorian, which differs by up to 13 days.
What about future dates?+
It works as long as the calendar stays Gregorian. The math doesn't change.