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Age Calculator

Enter your date of birth to see your exact age in years, months and days — plus how many days are left until your next birthday.

Result

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How this calculator works

Age is a calendar measurement, not a stopwatch reading. Turning it into a number of milliseconds and dividing by 365 introduces errors around leap years and time zones — the reason many online calculators are off by a day. This tool compares the calendar components directly, so the result is the same whether you open it in São Paulo, London or Tokyo.

The remaining days are counted from the anniversary date, with the day clamped to the length of the target month. That is why 31 January to 1 March reads as one month and one day in every year, leap or not.

Frequently asked questions

How is my exact age calculated?

We count complete calendar years first, then complete months, then the remaining days. Adding one month to 31 January gives 28 February (or 29 February in a leap year), which is how people normally read a date span.

Does it handle leap years and 29 February?

Yes. Leap years follow the full Gregorian rule, so 1900 is not a leap year but 2000 is. If you were born on 29 February, your birthday in a common year is shown as 1 March.

Can I calculate my age on a past or future date?

Yes. The second field defaults to today, but you can change it to any date to see how old you were, or will be, on that day.

Is my date of birth sent anywhere?

No. The calculation runs entirely in your browser. Nothing you type is uploaded or stored.

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