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Day of the Week Calculator — Free Online Calculator

Finds what day of the week any given date falls on.

What is it?

The day-of-week calculator tells you which day of the week (Monday, Tuesday, etc.) any calendar date falls on — past or future.

Formula

Zeller's congruence or Tomohiko Sakamoto's algorithm (common implementations). For any Gregorian date, the day can be computed from year, month, and day values alone.

Example

What day was 1 January 2000? → Saturday. What day is 19 June 2026? → Friday.

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