Age Calculator
Enter your date of birth and (optionally) a target date. Get exact age in years/months/days, total days lived, and countdown to next birthday.
Age
Detail
How age is calculated
Years are the primary unit — if you were born on 1990-06-15 and today is 2026-09-04, you're 36 years old and some change. The “some change” is months and days, calculated by walking forward from your last completed birthday. Total days lived is a simple date arithmetic in milliseconds divided by 86,400,000 (ms per day), which handles leap years and DST automatically.
Leap-day birthdays
If you were born on February 29, this calculator treats February 28 as your birthday in non-leap years for age-increment purposes — the standard convention in most jurisdictions and legal age calculations.
Time zones
The tool uses your local browser time zone. If you were born in a different time zone from where you are now, the year/month calendar age doesn't care — birthdays are always local — but the total-days number can shift by ±1 depending on how the date entry is interpreted.