Age Calculator
How it works
The years and months are counted off the calendar first, and whatever is left over is counted as days. That order matters: months are 28 to 31 days long, so working the other way round — subtracting the day of the month and patching up a negative — has to borrow from a month, and there is no month that always works. Someone born on 31 January is one month and one day old on 1 March, not one month and minus thirty days.
The next-birthday countdown reads 0 days on the day itself rather than jumping to next year, which is what the age above says too: it turns over to a whole number of years and no months on exactly that date.
Dates are handled in UTC from end to end, so the answer does not shift by a day depending on where you are. Counting the days between two dates that are not a birthday? The date difference calculator does that.
Frequently asked questions
How is the age worked out?
In real calendar months, not in 30-day ones. Someone born on 15 March 1994 is 32 years, 5 months and 9 days old on 24 August 2026 — the years and months are counted off the calendar first, and only the leftover days are counted as days. Dividing the total days by 365.25 gives a different, wronger answer.
What happens with a birthday on 29 February?
In a year that has no 29 February, the birthday is treated as falling on the 28th — for the age and for the countdown alike, so the two can never disagree with each other. In a leap year it falls on the 29th itself.
Is my date of birth sent anywhere?
No. The calculation runs in your browser in JavaScript. Nothing you type is uploaded, stored or logged.