Why not just divide the days by 365?

Because that ignores leap years and the different lengths of months, so it drifts. Walking the calendar month by month gives the answer a person would give, which is the one that matters for an age.

How is a 29 February birthday handled?

The next birthday falls back to 28 February in common years, which is the convention most legal systems use. Some jurisdictions use 1 March instead, so check if it matters for a formal purpose.

Can I work out an age on a past or future date?

Yes — set the second date to whatever you need. That is the usual way to answer eligibility questions, where the age on a specific cut-off date is what counts.

Does the time zone matter?

It can. The calculation uses your device's local date, so near midnight or across a date line the reference day may not be the one you intend. Age is tied to a calendar rather than an instant.

Age Calculator

Exact age in years, months and days — plus the next birthday.

Everything runs inside your browser. Your files never leave your device.

Result

The result appears here as you type.

Ask about Age Calculator

Questions about what this tool does, which option to pick, or what it can and cannot handle.

The question you type here is sent to an AI provider to be answered — your files and whatever you put in the tool above are not, and the assistant cannot see them. Answers are generated and can be wrong. The tool itself is not guessing: it runs deterministic code on your device.

About the Age Calculator

Working out an exact age is harder than subtracting two years, because months have different lengths and February changes size every four years. This gives the exact interval between a birth date and today, or any date you choose, in years, months and days.

The calculation walks the calendar rather than dividing by 365.25. That distinction matters at the edges: someone born on 31 January is one month old on 28 February in most conventions, and dividing by an average year length gives an answer that is close and wrong. Walking the calendar gives the answer a person would give.

The next birthday countdown is the part most people actually came for, and it handles the 29 February case by falling back to the 28th in common years, which is the convention most jurisdictions use for legal purposes.

Total days lived is included because it is a genuinely interesting number and because it is the figure needed for anything measured in days rather than years — visa durations, residency qualifying periods, some insurance calculations.

The one thing to know about time zones: this uses your device's local date. If you are calculating across a date line, or close to midnight, confirm the reference date is the one you meant. Age is a civil concept tied to a calendar rather than an instant, so the answer depends on which calendar you are asking about.

For intervals between two arbitrary dates rather than a birth date, the date difference calculator on this site is the better fit, since it does not assume one of them is in the past.

How to use it

1Enter the date of birth.
2Leave the second date as today, or set it to work out an age at a particular moment.
3Read the exact age in years, months and days, and the total days lived.
4Check the next birthday countdown, which handles 29 February by falling back to the 28th in common years.

Questions

Why not just divide the days by 365?: Because that ignores leap years and the different lengths of months, so it drifts. Walking the calendar month by month gives the answer a person would give, which is the one that matters for an age.
How is a 29 February birthday handled?: The next birthday falls back to 28 February in common years, which is the convention most legal systems use. Some jurisdictions use 1 March instead, so check if it matters for a formal purpose.
Can I work out an age on a past or future date?: Yes — set the second date to whatever you need. That is the usual way to answer eligibility questions, where the age on a specific cut-off date is what counts.
Does the time zone matter?: It can. The calculation uses your device's local date, so near midnight or across a date line the reference day may not be the one you intend. Age is tied to a calendar rather than an instant.