How to use Age Calculator

Enter the date of birth.
Set Age on this date, or leave it empty for today.
Leave Show the next birthday ticked for the countdown.
The age, the totals and the next birthday update as you change the fields.

Example: Age Calculator

Work out the age of someone born on 15 May 2000, measured on 22 September 2026.

You add

Date of birth 2000-05-15, Age on this date 2026-09-22, Show the next birthday on.

You get

26 years, 4 months and 7 days, or 9,626 days, or 316 completed months. The next birthday is Saturday 15 May 2027, 235 days later, turning 27.

Options

Age on this date: Leave it empty to use today, or set a date to measure from, such as a competition cut-off or a visa form.
Show the next birthday: Adds the weekday, the date, the days remaining and the age reached. Turn it off for the age alone.

Supported inputs and limits

Calendar dates only, so the hour of birth never changes the answer. The date to measure from cannot come before the date of birth, and years run from 0001 to 9999. A birthday on 29 February is treated as 1 March in years without a 29 February, and that rule is printed with the result. Total months counts completed months. Legal age rules differ by country, so check the rule that applies before using the number on an official form.

Where your input is processed

This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

Why a 29 February birthday needs a rule

A leap day is missing from most years, so an age calculation has to decide when someone born on 29 February has a birthday. This calculator uses 1 March in common years and prints that rule when it applies. Other places choose 28 February instead, and the difference is one day. The arithmetic also assumes a person turns a given age at the start of the birthday, not at some time during it. Neither rule is universal, so check the rules the form actually uses.

Questions about Age Calculator

How is the age worked out?

Whole calendar years first, then leftover months, then leftover days. Born 15 June 2000 and measured on 25 September 2026 gives 26 years, 3 months and 10 days.

What happens for someone born on 29 February?

The tool treats it as 1 March in common years. Born 29 February 2000 and measured on 28 February 2026 gives 25 years, 11 months and 30 days; on 1 March 2026 the age reads exactly 26.

Can I work out an age on a future date?

Yes, as long as the birth date is earlier. Useful for a cut-off that has not arrived, such as the first day of a season.

Does the calculator use my time zone?

No. It works from the two calendar dates, so the result does not shift across midnight or when you travel.

Project manager: Tony Hines · Content updated 29 September 2026 · Report a problem

Age Calculator

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