How to Use the Birth Day of the Week Calculator
Enter your date of birth and instantly find out what day of the week you were born. "Was I born on a Monday, or did I arrive on a lazy Sunday?" is a question most people wonder about at some point. The day of the week people are born on is often brought up as a fun fact or tied to old folk sayings, so it makes for a nice piece of trivia to know.
The calculation is straightforward. Based on the date you enter, the tool figures out the weekday of your birth, and it also shows which weekday your birthday falls on this year (or next year, if it has already passed). The reason your birthday lands on a different weekday each year is that a year is close to 365.25 days rather than exactly 365, so the weekday drifts forward over time — this calculator lets you see that drift directly.
Note that weekdays are calculated using the Gregorian calendar, the system used worldwide today, so very old dates may not match the calendar that was actually in use at the time. It's also fun to plug in the birth dates of family or friends and compare the weekdays you were all born on.
Frequently Asked Questions
This calculator uses the Gregorian calendar, the system used worldwide today. Very old dates before 1582 may differ from the calendar actually in use at that time.
A year has 365 days, which isn't evenly divisible by 7, so the weekday shifts forward by one each year. In leap years, it shifts forward by two.