Age Calculator
Enter a birth date and get the precise age — not a rounded year count, but years, months and days, plus the total in days and the next birthday countdown.
100% private — everything runs in your browser, nothing is ever uploaded.
How to use it
- Enter the date of birth.
- Optionally change the reference date from today to any other date.
- Read the exact age and the totals below.
Why it stays private
A birth date combined with a reference date is personal data. The calculation happens in your tab — nothing is submitted or remembered.
Questions
How are months counted?
The same way people count them: whole calendar months first, then the leftover days. So someone born on 31 January is one month older on 28 February — calendars are irregular, and the tool follows the calendar rather than an average month length.
Does it handle leap years?
Yes. Leap days are part of the calendar arithmetic, and a person born on 29 February has their birthday counted on 1 March in non-leap years, which is the usual legal convention.
Can I work out an age at a date in the past?
Yes — set the reference date to any past or future day, for instance a historical event or an upcoming milestone.