Day of the Week
Find what day of the week any date falls on
How to use Day of the Week
- 1Enter any calendar date you are curious about.
- 2Pick the calendar system if a choice is offered, usually Gregorian.
- 3Read which weekday that date falls on.
Finding the weekday of a date
Based on Zeller's congruence or a known anchor, accounting for leap yearsWeekday calculation chains from a reference date, stepping through the known 400-year leap-year cycle of the Gregorian calendar.
Because the pattern repeats every 400 years, the same date lands on the same weekday in years 400 years apart.
Frequently asked questions
Does it work for any year?
For the Gregorian calendar it covers modern and most historical dates back several centuries.
Why do leap years matter?
They shift every date after February 29 by one weekday, so the rule must track them.
What about the Julian calendar?
Older dates used the Julian system with different leap rules; pick it if your date predates the switch.