Age calculator
Exact age in years, months and days, today or on any date you choose, plus the weekday of birth and a countdown to the next birthday.
Guide
How to use it
- Pick the date of birth.
- Leave the second date empty for age today, or set it for age on a deadline, a start date or 31 August for school-year questions.
- Read the tiles: exact years, months and days, total days and whole months, then the weekday born and next-birthday countdown beneath.
Examples
Worked examples
Born 14 March 1961, age on 6 April 2026: set both dates and read 65y 0m 23d, the years-months-days format official forms ask for.
Born 30 August 2022, age on 31 August 2026: exactly 4, so they start reception that September. Born two days later, they wait a year.
Enter any date of birth and the weekday appears: 8 August 1990 was a Wednesday, settling the family argument in one line.
Method
How it works
Exact age is calendar arithmetic, not division by 365: whole years first, then whole months, then leftover days, borrowing real month lengths when the day-of-month has not arrived yet. Leap years fall out of the calendar itself, and 29 February birthdays roll to 1 March in common years for the countdown.
Dates of birth are sensitive data, which is why this runs entirely in your browser: nothing typed here is transmitted, logged or stored.
FAQ
Frequently asked questions
How is age in years, months and days calculated?
Whole years first, then whole months, then leftover days, borrowing from the real calendar when needed. Someone born 31 January is 1 month 0 days old on 28 February in a common year, month lengths are respected.
Can I work out an age on a specific date?
Yes, set the second date. That answers form questions like age on 1 September for school years, or age on a competition's closing date.
How are leap-year birthdays handled?
A 29 February birthday exists only in leap years; in other years the next-birthday countdown lands on 1 March, matching how UK law treats it.
What day of the week was I born?
Shown automatically under the tiles. The calendar repeats over long cycles, so this is computed exactly, not looked up.
Why does the school year use 1 September?
In England and Wales, a child's school year is set by their age on 31 August. Set the second date to 31 August of the relevant year and read the years tile.
Is the date of birth I enter stored?
No. The calculation happens in your browser and nothing is transmitted or saved anywhere.
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