About AgeCalc

AgeCalc is a free age calculator that runs entirely in your web browser. Enter a date of birth and it works out the exact age in years, months and days, the total days, months, weeks and hours lived, the weekday of the birth, and the countdown to the next birthday.

Why browser-based?

A date of birth is personal information — it's on identity documents and unlocks accounts. Plenty of calculator sites send whatever you type to their servers. AgeCalc takes the other path: all the arithmetic happens in the page itself, on your own device, so the dates you enter are never transmitted anywhere. There's no sign-up, nothing is stored, and the calculator even works offline once the page has loaded.

How accurate is it?

The calculator does true calendar arithmetic — it borrows days from the real months and counts every leap day — rather than the rough "days ÷ 365" shortcut. The same method, done by hand, is explained in our guide to calculating age.

What it costs

Nothing. AgeCalc is free to use, with no account and no limits. The site is supported by advertising, which keeps the tool free for everyone.

Who it's for

Parents checking a school enrolment cutoff, anyone filling a form that asks for age on a specific date, and everyone who has ever wondered how many days old they are — or which weekday they were born on.

Questions or ideas? See our contact page.