In short: An age calculator works out exact age in years, months and days from a date of birth to today or any other date, and the days until the next birthday.
About Age Calculator
Working out an exact age sounds easy until months of different lengths and leap years get involved. This calculator counts complete years, then complete months, then remaining days — the way ages are normally stated — and also gives the totals in months, weeks and days.
You can calculate the age on any date, not just today, which is useful for eligibility rules (“must be 18 on the day of the event”), historical questions or planning. It also counts down the days to the next birthday and tells you which weekday it falls on.
How to use Age Calculator
- Enter the date of birth.
- Leave Age on date as today, or choose another date.
- Read the exact age and the totals.
- See how many days remain until the next birthday.
Examples
Born 20 May 2008: on 1 May 2026 that person is 17 years, 11 months and 11 days old — not yet 18.
For someone born on 29 February, this calculator treats the birthday in non-leap years as 1 March. Conventions differ between countries, some use 28 February.
Frequently asked questions
How are months counted?
A month is complete when the same day number is reached in the following month. If that day does not exist (e.g. 31st), the month ends on the last day.
Does it work for dates before 1970?
Yes. Any date supported by your browser’s calendar works.
Why do some countries count age differently?
Traditional East Asian age reckoning starts at one at birth and adds a year at the new year. This calculator uses the international convention.
Is my birth date saved?
No. Everything is calculated locally and nothing is stored.
Updated November 2026 · Free, no signup · How we build and test tools