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Age calculator

Exact age from a date of birth — years, months and days, and the total days behind it. The sum runs in your browser.

Nothing is sent anywhere — the sum happens in your browser.

Put a date in and the answer appears here.

How it works

It counts whole months first, then the days left over — which is not the same as dividing by 30.44.

An age in years is easy. The months and days after it are where calculators go wrong, because months aren't the same length and the answer depends on which ones you crossed.

This one counts the whole months between the two dates, moves the birth date forward by exactly that many, and measures what remains in days. When that lands on a day the target month doesn't have — 31 January plus one month — it clamps to the last day of the month rather than rolling into the next one.

Nothing is uploaded. The date never leaves the page, there is no request to a server, and closing the tab is the whole of the privacy policy for this tool.

Worked examples

Both dates are given in each, so these stay true whenever you read them. Every answer is produced by the same function the tool above uses.

Choose

Born 11 February 1997, worked out on 11 August 2026

You get

“29 years, 6 months, 0 days — 10,773 days in total.”

Choose

Born 31 January 2000, worked out on 1 March 2025 — the month-end case

You get

“25 years, 1 months, 1 days — 9,161 days in total.”

Choose

Born 29 February 2000, worked out on 28 February 2025

You get

“24 years, 11 months, 30 days — 9,131 days in total.”

Where calculators disagree

Two cases have no correct answer, only a convention. Here are the ones this tool picked.

The end of a short month. From 31 January, when does one month have passed — 28 February, or 3 March? This tool says 28 February, so 31 January to 1 March reads as one month and one day. Some calculators say nought months and 29 days. Neither is wrong; they answer slightly different questions.

Being born on 29 February. In a common year this tool treats 28 February as the birthday, which is what most people do. Some legal systems use 1 March instead — for the age of majority in England and Wales, for instance. If a date matters legally, this is a toy and that is a solicitor's question.

Time of day is ignored throughout. Ages are counted in whole calendar days, so the answer doesn't change depending on whether you check in the morning or the evening.

Questions

Is my date of birth stored or sent anywhere?
No. The calculation happens in your browser and the date is never sent to us. There's no account, no cookie needed for it, and nothing to delete afterwards.
Why does it say months instead of just days?
Because that's how people say ages, especially for children. The total days are there too, in the row underneath.
Does it handle leap years?
Yes, including the century rule — 2000 was a leap year, 1900 wasn't. A 29 February birth date works, and the section above says which day it counts as in a common year.
Can I use this for an official form?
For checking your own arithmetic, yes. For anything legal, no — the month-end and leap-day conventions above are choices, and the one that matters is whichever the form's rules specify.
Why is my age different from another calculator?
Almost always one of the two conventions above, and almost always in the months-and-days part rather than the years. The total days should agree everywhere.