Day of the Week Calculator

Enter any date — past or future — and this calculator instantly tells you the day of the week. It works for your birthday, a historical event, a future deadline, or any date you are curious about, using the standard Gregorian calendar.

Enter your date of birth and the calculator returns the exact weekday you were born on, plus whether it was a weekend and which day of the year it was. Many people are surprised to learn they were born on a weekend.

Yes, for dates in the Gregorian calendar (used worldwide since 1582, and in most English-speaking countries since 1752). It correctly handles leap years, so weekdays for dates decades in the past or future are accurate.

It is the count of days from January 1 to your date — January 1 is day 1 and December 31 is day 365 (or 366 in a leap year). It is handy for scheduling, data logging, and understanding how far into the year a date falls.

Calendars follow a fixed 7-day cycle, so the weekday of any date can be computed from the number of days since a known reference date, accounting for leap years. This tool uses your device's built-in date engine, which implements those rules precisely.