Age Calculator
Your exact age in years, months and days — plus total days lived and how long until your next birthday.
Defaults to today. Change it to work out an age on any date.
How to use it
- Enter your date of birth.
- Leave the second date as today, or change it to work out your age on any past or future date.
- Everything updates instantly — no button to press.
Why age is harder to calculate than it looks
Subtracting two years is easy. Everything after that is not, because the calendar is not made of equal parts.
Months are 28, 29, 30 or 31 days long, so "one month" has no fixed length, and the answer to "how many months old am I" depends on which months you happened to live through. Years are 365 days except when they are 366. A leap year is every fourth year, except century years, except century years divisible by 400 — which is why 1900 was not a leap year and 2000 was.
This page counts the way people actually count: full years first, then the leftover full months, then the leftover days. That is why the months figure is not simply the years multiplied by twelve, and why the day count is exact rather than an estimate.
What people need an exact age for
- Forms and applications — passports, visas and school admissions usually want age as of a specific date, not today. Change the second date to that date.
- Eligibility — voting, a driving licence, a pension or an age limit that falls on an awkward day.
- Medical and legal paperwork, where age in completed years on a given date is the figure that counts.
- Curiosity — the total days figure is the one most people came for.
Frequently asked questions
How is the years, months and days figure worked out?
The same way you would do it on paper: subtract the day, borrowing from the previous month if it goes negative, then the month, borrowing from the year. That is why it is calendar-correct rather than an approximation from total days.
Why does the total months figure not match years times 12?
Total months counts whole completed months and ignores the leftover days. Someone who is 30 years and 29 days old has completed 360 months, not 361.
What happens if I was born on 29 February?
A leap-day birthday falls on 1 March in non-leap years in this calculation, which is the convention most countries use for legal age.
Is my date of birth stored anywhere?
No. The date never leaves your browser, and nothing is saved when you close the tab.