DocomintDay of the Week Finder
Find what day of the week any date fell (or will fall) on, plus its day-of-year and quarter.
Finds the weekday for any date — a birthday, a historical event, a future appointment — instantly rather than counting weeks on a mental calendar, plus three related figures (day of year, ISO week number, and calendar quarter) that come up in scheduling and reporting contexts.
Example: August 8, 2026 falls on a Saturday — the 220th day of the year, in ISO week 32, within Q3.
How it works
- Enter any date, past or future
- Press Find Day
- The weekday, day-of-year number, ISO week, and quarter all appear instantly, computed on your device
Frequently asked questions
How far back or forward in time does this work?
It works for any date the browser's Date object can represent — effectively many thousands of years in either direction — though results for dates before widespread adoption of the Gregorian calendar (pre-1582 in most of Europe) won't match historical calendars actually in use at the time.
What calendar system does this use?
The Gregorian calendar — the internationally standard calendar used by virtually all modern software, and the one in civil use across most of the world today.
Is my numbers uploaded anywhere?
No — Day of the Week Finder runs entirely in your browser using JavaScript/WebAssembly. Your numbers is never sent to a server.