Why does the age only change on the birthday?

This is exact age: the number of complete years actually lived. Some cultures count age differently — East Asian reckoning starts at one at birth and adds a year at new year — which is why the number here can be one or two lower than a traditional count.

How is 29 February handled?

Common years have no 29 February, so the anniversary is treated as 28 February, which matches most administrative practice. In leap years it stays on 29 February.

DATE AND TIME · CALCULATED IN YOUR BROWSER

Age Calculator

Enter a birth date to get an exact age, total days, and a countdown to the next birthday.

Enter a valid date to count to.

Input

Date of birth

As of

About this tool

Enter a birth date and the date to count to, and you get an exact age in years, months, and days. The year only ticks over on the birthday itself, so a birthday later this month still reads as the previous age — the same way official records treat it. You also get total days, total weeks, the weekday you were born on, and how long until the next birthday.

How it works

Enter the date of birth.
Change the "as of" date if you need something other than today.
Read the exact age, total days, and next-birthday countdown.

Assumptions

Counted on the calendar rather than guessed from the browser time zone. Everything runs locally; the birth date is never sent anywhere.

Privacy

Every calculation runs inside this browser. Dates and birthdays are never uploaded, stored, or written to the URL or any log.

Frequently asked questions

Why does the age only change on the birthday?: This is exact age: the number of complete years actually lived. Some cultures count age differently — East Asian reckoning starts at one at birth and adds a year at new year — which is why the number here can be one or two lower than a traditional count.
How is 29 February handled?: Common years have no 29 February, so the anniversary is treated as 28 February, which matches most administrative practice. In leap years it stays on 29 February.

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