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Age Calculator

Calculate an exact age in years, months and days from a date of birth.

Details

Your Results

What Age Calculator does

Age is counted by the calendar rather than by dividing days, because months have different lengths and leap years add a day. Subtracting the years alone gives the wrong answer for anyone whose birthday has not yet passed this year.

This works through years, then months, then days, borrowing correctly from the previous month, which is how age is conventionally expressed.

  • Exact age in years, months and days
  • Correct handling of month lengths and leap years

How to use Age Calculator

  1. 1

    Enter the date of birth

    The age is calculated against today's date.

  2. 2

    Read the breakdown

    Years, months and days are shown as a single expression of age.

Example

Why subtracting the years is not enough

Input

Born 14 March 1990, today is 8 September 2026

Output

36 years, 5 months, 25 days

Someone born in December 1990 would still be 35 on this date. The year difference alone is wrong for everyone whose birthday falls later in the year than today.

When to use it

Completing a form accurately

Applications, insurance and medical forms often want an exact age rather than a birth year.

Checking an eligibility threshold

Confirm whether someone has reached an age boundary on a specific date rather than approximately.

Limits and known behaviour

  • Age is calculated against your device's current date in your local time zone. Someone on the other side of the world may already be a day ahead.
  • The result is exact to the day; times of day are not considered.
  • Different legal systems count age differently. Most compute it as here, but East Asian age reckoning traditionally counts differently, and some legal thresholds are reached on the day before a birthday.
  • Where a birthday falls on 29 February, the day it is observed in a non-leap year is a convention rather than a fact, and different jurisdictions treat it differently.
  • The calculation uses the Gregorian calendar throughout.

Privacy and data handling

Runs entirely in your browser

  • The calculation runs in this page. Nothing you enter is transmitted or stored.
  • The tool works offline once the page has loaded.

Site-wide data handling, including analytics and advertising, is described in the privacy policy.

Frequently asked questions

Why does my age in months look wrong?

Because months are not equal. The month component counts completed calendar months, so a birth on the 31st followed by a short month produces a result that looks off but is calculated conventionally.

How are leap years handled?

Correctly, through the calendar itself rather than by approximating a year as 365.25 days. That approximation is where most hand calculations drift by a day or two.

What happens to a birthday on 29 February?

The calculation follows the calendar. Which day such a birthday is observed on in a non-leap year is a matter of convention and, in some legal contexts, of statute: some jurisdictions treat 28 February as the day the age is reached and others 1 March.