How Age Calculator works

Calculate exact age in calendar years, months and days, plus total weeks, next birthday and day of birth.

The formula

Age is counted across real calendar anniversaries and month boundaries, not by dividing elapsed days by 365.

A practical example

Someone born on 29 February 2000 is 25 years and 1 day old on 1 March 2025.

Important limitations

The result uses calendar dates without a time of day. Leap-day birthdays are clamped to the last valid day in non-leap years.

Frequently asked questions

Is age calculated using 365 days per year?

No. The calculator advances through actual calendar years and months.

Can I calculate age on a past date?

Yes. Choose any calculation date on or after the date of birth.