Day of the Week Calculator
Find the day of the week for any date in the past or future, with the day of the year, ISO week number and whether it's a leap year. Free and instant.
Any date, any year
Pick a date to see which day of the week it falls on, whether it's your birthday in 1990 or a meeting next year. The result also shows the day of the year (from 1 to 365, or 366 in a leap year), the ISO week number used in business calendars across Europe and Asia, and whether the year is a leap year. The calculator opens on today's date.
How to use it
- 1
Pick a date
Choose any day, month and year.
- 2
Read the weekday
The day of the week appears at once.
- 3
Check the details
See the day of the year, ISO week number and leap year status.
Frequently asked questions
What day of the week was I born?
Enter your date of birth. The Age Calculator also shows this, along with your exact age.
What is the ISO week number?
In the ISO 8601 system, weeks start on Monday and week 1 is the week with the year's first Thursday. So the first days of January can belong to the last week of the previous year.
Which years are leap years?
Years divisible by 4, except century years, which must be divisible by 400. So 2024 and 2000 are leap years, but 1900 and 2100 are not.
Is anything sent to a server?
No. Everything is calculated in your browser, and nothing you type is stored or sent anywhere.