About the age calculator
Age is counted in calendar months rather than by dividing days, because months are not the same length. Someone born on 31 January is one month old on 28 February in a common year, not on 2 March.
The result is the age a person has already reached, not the one they are approaching. The day before a birthday you are still the younger age, which is how age is counted everywhere except in a few traditional reckonings.
Frequently asked questions
- Is anything I enter sent anywhere?
- No. Every calculation runs inside your browser. Nothing you type - a date of birth, a salary, a list of numbers - is uploaded, stored or logged, and the page keeps working with the network disconnected.
- How is age worked out exactly?
- By counting whole calendar months from the date of birth and then the days left over, clamping to the end of a shorter month. Dividing the total days by 365.25, which some calculators do, drifts by a day or more and gets leap years wrong.
- What happens with a 29 February birthday?
- In a common year the next birthday falls on 1 March, which is the convention most legal systems use and the only one that never produces an impossible date. The age in years is unaffected.
- Can I find my age on a past or future date?
- Yes. Fill in the second date and the age is calculated as at that day rather than today.
Related everyday calculators
How your data is handled
Everything happens on your device. There is no upload, no storage and no logging. Closing the tab clears everything you entered.