How to use it
- Pick the date of birth. The answer appears at once; future dates are refused.
- The line under the big number gives the exact age as years, months and days.
- The chips add the total days lived, the countdown to the next birthday with its weekday, the weekday of the birth itself and the star sign.
How the age is counted
The way people count it, not the way a naive subtraction does. Full years first, then the leftover months, then the leftover days, with the borrow taken from the length of the actual previous month rather than from an average of 30.44. That is why the answer agrees with what a passport officer would write down.
A 29 February birthday is handled by the browser date object, which moves it to 1 March in a non-leap year. That is the usual convention in software and in most legal systems, though a few jurisdictions treat 28 February as the anniversary. If that distinction matters for a document, check the local rule rather than this page.
The chips
- Total days lived, counted from midnight to midnight.
- Days to the next birthday, and which weekday it falls on.
- The weekday of the birth.
- The star sign, by the usual date boundaries.
Questions
How do I work out my exact age?
Enter your date of birth. The large number is your age in full years, and the line below gives it as years, months and days.
Does my date of birth get sent anywhere?
No. The arithmetic happens in your tab. The date is remembered in your own browser local storage so you do not retype it, and it never reaches affpapa.org.
What about someone born on 29 February?
In a non-leap year the next birthday is counted as 1 March, which is how browsers and most legal systems treat it. In a leap year it falls on 29 February as you would expect.
Can I use it for someone else?
Yes. Nothing on the page assumes the date is yours, so it works for a child, a parent or a form you are filling in.
