Date Info (Weekday, Week, Leap Year)
Enter a date to see which weekday it falls on, which week and day of the year it is, and whether that year is a leap year. Week numbers use a simple rule that starts on 1 January with seven-day blocks, so they can differ from ISO week numbers.
- Enter or paste a date in the form 2026-10-25.
- The result lists the date, weekday, week and day of the year, and whether it is a leap year.
- Swap the year to check which weekday a holiday falls on.
FAQ
Why does the week number differ from my calendar?
Week 1 starts on 1 January here and weeks run in blocks of seven days. ISO-8601 instead starts on Monday and defines week 1 as the week containing 4 January, so the two can differ by one around the turn of the year.
Is the weekday local?
The weekday comes from the date as parsed in your browser's time zone. A date-only input has no offset; if you include a time, the echoed date is shown in UTC and may differ by a day.
How is a leap year decided?
By the Gregorian rule: divisible by 4 and not by 100, or divisible by 400. So 2000 is a leap year and 1900 is not.