Age Calculator
Work out your exact age in years, months and days from your date of birth, and see how long until your next birthday.
Defaults to today
How is age calculated?
Your age is the time that has passed between your date of birth and a chosen date, by default, today. The calculator counts complete years first, then the remaining months, then the remaining days, handling months of different lengths and leap years correctly.
It also totals your age in days, weeks and months, and counts down the days to your next birthday, which is handy for planning celebrations or working out eligibility dates.
Worked example
Someone born on 15 March 1990, calculated on 13 August 2026, is 36 years, 4 months and 29 days old.
That is roughly 13,300 days, and their next birthday is about 214 days away.
Frequently asked questions
Does it handle leap years?
Yes. The calculation uses real calendar dates, so leap years and months of different lengths are handled correctly.
Can I calculate age on a future or past date?
Yes. Change the “age at” date to work out how old someone was, or will be, on any date.
What about someone born on 29 February?
Their age increases each year; in non-leap years the calculator treats the day count relative to the actual calendar, so results stay accurate.
Is my date of birth stored?
No. Everything is worked out in your browser and nothing you enter is saved or sent anywhere.
Why does it show months and days as well as years?
Whole years alone can be imprecise for things like eligibility or milestones, so the breakdown into months and days is often more useful.
Figures last reviewed on 13 August 2025.
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