Method and assumptions
Compare a birth date with any reference date to calculate exact age, total days lived, and time until the next birthday. The result accounts for whether the birthday has already occurred in the selected year.
Age Calculator
Find your exact age and the days until your next birthday.
Reviewed: 2026-07-21
How to use it
- Choose the date of birth.
- Change the reference date if you need age on a past or future date.
- Review exact age and the countdown to the next birthday.
When it helps
- Checking age for a form or application
- Finding age on a specific date
- Counting down to the next birthday
How to verify the result
Check input units and reference dates first. For an important decision, compare the result with an official source or original document. A rounded display can differ slightly from the underlying value.
Frequently asked questions
How is exact age calculated?
Subtract the birth year from the reference year, then subtract one if the birthday has not yet occurred in that reference year.
Is a newborn zero years old?
Yes. Exact age counts a child as zero until the first birthday.
Can I calculate age on a future date?
Yes. Set the reference date to any future date to see the age on that day.