Day of the Week Calculator
Find the weekday of any date, past or future.
What day was it?
Choose any date and the calculator names the weekday. It is handy for birthdays, anniversaries, historical dates and planning ahead.
Example
4 July 2026 is a Saturday. It is day 185 of the year and falls in the third quarter.
Other details shown
- Day of the year: how far through the year the date is, counting 1 January as day 1.
- ISO week number: weeks start on Monday, and week 1 is the one with the year’s first Thursday.
- Leap year: years divisible by 4, except century years not divisible by 400.
Frequently asked questions
Does it work for dates in the past?
Yes. It uses the modern Gregorian calendar for all dates, which is a good guide for most uses.
Why do some calendars number weeks differently?
Countries differ on whether weeks start on Sunday or Monday. This tool uses the ISO standard, which starts on Monday.
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