About this tool
A day of week calculator tells you which weekday any calendar date falls on, whether it is your birthday, a past anniversary or a deadline next year.
Pick a date and the page shows the weekday in big letters, the full date, which day of the year it is, the ISO week number, whether the year is a leap year, and every date in the same month that falls on the same weekday.
What day of the week was I born? Enter your birth date and read the first line. For example, January 1, 2000 was a Saturday, and it is day 1 of 366 because 2000 was a leap year. Why does week number matter?
Many schedules and payroll systems number weeks of the year, and this tool uses the ISO 8601 rule, where weeks start on Monday and week 1 is the week containing the first Thursday of the year.
A date in early January can therefore belong to the last week of the previous year, and the page says so.
The calculation uses the Gregorian calendar, so very old dates before its adoption in some countries may differ from historical records.
Leap years follow the usual rule: divisible by 4, except century years not divisible by 400. To count the days between two dates, use the Date Calculator, and for the next birthday try the Birthday Countdown.
Your date is processed in your browser and is never sent or saved.
How to use
- Pick a date with the date field, or type it in.
- Read the weekday shown in big letters at the top.
- Check the day of the year, week number and the other dates with the same weekday.