Calculators
Age calculator
Calculate completed years, elapsed days and the next birthday for a chosen date.
Calculation
Calculated in your browser. Your entries are not uploaded.
Calculated in your browser. Your entries are not uploaded.
How to use this calculator
- Choose the calculation and input format.
- Enter your values or load the worked example.
- Read the result, then copy or download it as text.
Calculation rules
Completed years count birthdays reached on the comparison date. Someone born on 2000-02-29 is 25 on 2025-02-28 under the February 28 policy, or 24 under the March 1 policy. The selector makes this convention explicit; legal rules may differ by jurisdiction.
Questions and answers
What happens when the comparison date is a birthday?
Elapsed days measure the date-only interval since birth. If the comparison date is a birthday, the next birthday is today and the countdown is zero. Dates use the Gregorian calendar; time of birth is not included. A next birthday beyond year 9999 is unavailable.