What is an age calculator?

An age calculator tells how many years, months and days a person has between their birth date and a reference date (usually today). This tool computes the exact age to the day, the total days, weeks, months and hours lived, and tells you when the next birthday falls and which weekday the birth was. Everything is computed in your browser, no data is sent.

How to use this tool

Pick the date of birth.
Leave the reference date blank to use today, or pick another date (for example, a future age).
The exact age, totals and next birthday update instantly.

Typical use cases

Compute the exact age for forms, insurance or paperwork.
Find out how many days old a baby or a pet is.
Plan celebrations and gifts with the exact day of the next birthday.

Frequently asked questions

How are months counted in an age?

Age is counted in completed anniversaries: if you were born on March 15, on May 14 you have 0 months and 29 "extra" days, and on May 15 you turn 2 months. The calculator applies that anniversary rule.

What about leap years?

The calculation uses the real calendar: February of a leap year has 29 days, so ages around that date are exact.

Age Calculator