How to calculate your age
Select your date of birth and the date you want to measure against. The reference date starts at today. Choose an anniversary convention if the birth date is 29 February, then calculate. The result includes calendar age, elapsed calendar days and the next birthday.
How the result is calculated
We count complete years first, then complete months, then the remaining days. When an anniversary or month-end date is unavailable, it is clamped to the last available day, with a separate 1 March option for leap-day anniversaries. We calculate the total day count independently.
Worked example
A person born on 15 June 2000 is 25 years, 2 months and 5 days old on 20 August 2025. The result measures calendar dates and does not use a birth time.
Read our calculation methods and limits for date ranges, rounding and calendar conventions.