Find out which day of the week any date falls on: your birthday, a historic day or a date in the future.
Last updated: October 31, 2026
The Gregorian calendar, leap years and week numbers
This tool shows which day of the week a date falls on, which day and week of the year it is, and how many days it is from today. Use it to find the day you were born, check what day a meeting or holiday lands on, or look up a historic date. Weekdays repeat in a 7-day cycle. A normal year has 365 days, which is 52 weeks plus 1 day, so a date moves forward one weekday each year: a birthday on a Monday this year falls on a Tuesday next year, unless 29 February comes in between, in which case it moves two days. The leap year rule: years divisible by 4 are leap years, except those divisible by 100 but not by 400 (such as 1900 and 2100). 2000 was a leap year. The week number follows ISO 8601: weeks start on Monday and week 1 is the week that contains the year's first Thursday. This is the standard in Europe; some US calendars count weeks from Sunday and can differ by one. Dates use the Gregorian calendar, in use since 1582.
Common questions about days of the week
Enter your date of birth in the date box. The result card shows the weekday, for example "Wednesday", in large type.
Other tools you may find useful
Your birthday or any date you're curious about.