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Age Calculator
Work out an exact age in years, months and days from a date of birth.
How age is calculated
Age in years is the number of complete years between the two dates. We start from the year difference, then subtract one if the birthday hasn't yet occurred in the target year. The leftover months and days are counted by "borrowing" from the previous month where needed — the same way you'd do it by hand.
Worked example
Someone born on 1 January 1990, measured on 18 June 2026, is 36 years, 5 months and 17 days old — because their 2026 birthday (1 January) has already passed, then we count the months and days to 18 June.
FAQ
Does it handle leap years?
Yes. The calculation uses real calendar dates, so leap days are counted correctly.
Can I check a future date?
Yes — set "age at date" to any date. If it's before the birth date, no age is shown.