Find out which day of the week any date falls on, whether it is in the past or the future. It also shows the week number, the day of the year and whether the year is a leap year.
| Week number (ISO) | – |
| Day of the year | – |
| Leap year? | – |
| Days until or since today | – |
How it works
The calculator reads the date and uses the calendar to find the weekday. The ISO week number follows the international standard, where weeks start on Monday and week 1 is the week with the first Thursday of the year. A year is a leap year if it is divisible by 4, except century years, which must be divisible by 400.
Example
15 June 1990 was a Friday, in ISO week 24, and 1990 was not a leap year.
Frequently asked questions
How do I find what day I was born?
Enter your date of birth and read the day of the week.
What is the ISO week number?
A standard week numbering where weeks run Monday to Sunday and week 1 contains the first Thursday.
Is 2100 a leap year?
No. Century years are leap years only if divisible by 400.
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This calculator is for general use.