Birth Year Calculator
What year was I born? Enter an age and whether the birthday has passed this year to get the birth year, the exact range of possible birth dates, and the year of the next birthday.
How it works
Birthday already passed this year: birth year = current year − age · birthday still to come: birth year = current year − age − 1 · not sure: one of those two years
Your age goes up by one on each birthday, so the same age points to two possible birth years depending on whether this year’s birthday has happened. The calculator also gives the exact window of birth dates consistent with the age: a person who is A years old on a given date was born after the same date A + 1 years earlier and no later than the same date A years earlier.
Worked example
A person who is 30 on October 5, 2026 and has already had their birthday this year was born in 2026 − 30 = 1996, somewhere between January 1, 1996 and October 5, 1996. They turn 31 in 2027. If the birthday were still to come, the birth year would be 1995.
Sources: Time and Date — Age calculator
Frequently asked questions
What year was I born if I am 30?
In 2026: 1996 if you have already had your birthday this year, 1995 if your birthday is still to come.
Why does the same age give two birth years?
Because your age only changes on your birthday. Before it you are still the age you turned last year, so subtracting your age from the current year overshoots by one.
How do I work out my age from my birth year?
Subtract the birth year from the current year, then subtract 1 more if your birthday has not happened yet. For an exact age in years, months and days use the age calculator.
What about people born on February 29?
This calculator treats a February 29 birthday as February 28 in common years. Some countries use March 1 instead for legal purposes, which only matters if you check the age on February 28.
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This calculator is for educational purposes. Double-check important results before acting on them.