Age calculator

How the age is worked out

Enter a date of birth and you get the age in years, months and days, the total number of days lived, and how long is left until the next birthday. The count runs in UTC, so it never jumps by a day when the clocks change.

Age is counted the way people do it: the years go up on the birthday itself, and the months and days that follow are the remainder since then. That is why the detail line can read “35 years, 2 months and 6 days” rather than a decimal.

Nothing is uploaded. The date stays in your browser, which matters for a piece of information as personal as a birthday.

Frequently asked questions

How is 29 February handled?

In a common year the next birthday falls on 1 March, which is how most registries treat it. The number of days lived is exact either way.

Why do the months not divide evenly?

Because months have different lengths. The tool takes the remaining days from the length of the previous month, so the remainder matches the calendar rather than an average month of 30.44 days.

Can I work out someone else's age?

Yes, any date works. For a date in the future the tool says so instead of returning a negative age.

What is the weeks figure for?

It is the days lived divided by seven, useful for babies and for anniversaries counted in weeks.