Day of the Week
Tells you what day of the week any date falls on — past or future. Pick a date, get the weekday, across the full calendar range the browser supports.
How to use
- Pick the date.
- The weekday appears immediately.
- For scheduling, step through candidate dates and note which land on working days.
- For historical dates, just enter them — the calculation works backwards too.
When you actually need this
- Checking whether a deadline or renewal date lands on a weekend before committing to it.
- Finding what weekday you were born, or any anniversary falls on this year.
- Planning an event around which dates give a Friday or Saturday.
- Verifying the weekday of a historical date in records or genealogy.
How the weekday is determined
The Gregorian calendar repeats its weekday pattern every 400 years — 146,097 days, exactly 20,871 weeks — which is why a formula can name the weekday of any date without a lookup table. The calculation here uses the proleptic Gregorian calendar: for dates before a country adopted it (1582 in Catholic Europe, 1752 in Britain and its colonies, later elsewhere), the weekday returned may differ from what contemporaries actually called that day, a detail that matters mainly to historians and genealogists.
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FAQ
Which time zone does Day of the Week use?
It uses your device's local time zone and calendar settings, so the result matches the dates you see elsewhere on your computer or phone. Nothing is converted to UTC behind the scenes.
Does Day of the Week handle leap years correctly?
Yes. The calculation works on real calendar dates rather than a fixed 365-day year, so February 29th, month lengths and century leap-year rules are all applied correctly.
Is the start or end day included in the count?
The tool shows the elapsed days between the two dates. If you need an inclusive count — for example counting today as day one of a challenge — add one to the result.