Age Calculator
Your exact age in years, months and days — plus a countdown to your next birthday.
Dates
Dates are handled in UTC, so a daylight-saving change can't shift your age by a day — a bug that affects a surprising number of online age calculators.
Your age
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Pick a date of birth to begin.
- Total months
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- Total weeks
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- Total days
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- Total hours
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- Born on a
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- Next birthday
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Next birthday
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How your age is calculated
Age in years, months and days is worked out by walking your date of birth forward one month at a time until the next step would pass the reference date. That sounds fussy, but it is the only method that matches what a calendar means by "one month".
The two cases that break naive calculators
- Short months. Subtracting fields separately and "borrowing" days from the previous month goes wrong whenever that month is shorter than your birth day-of-month — 31 January to 1 March is the classic failure. Here the date is clamped to the end of a short month instead.
- Daylight saving. Day counts computed in local time are truncated, so any span crossing a clock change comes out a full day short. Every date on this page is anchored to UTC, which never observes daylight saving, so the whole class of error disappears.
- 29 February birthdays. In a non-leap year the next birthday clamps to 28 February rather than rolling into March.
What you get
Alongside the exact years / months / days figure you get your total months, weeks, days and hours lived, the weekday you were born on, and a countdown to your next birthday including which weekday it falls on. Set Age as of to any date to check your age at a past or future moment — useful for eligibility cut-offs and application forms.