How to use the Age Calculator
The age calculator gives your exact age in years, months and days between a birth date and another date.
The formula
It subtracts the birth date from the chosen date, borrowing days from months and months from years as needed.
Worked example
Born 15 March 1990. On 15 March 2026 you are 36 years, 0 months and 0 days old.
Tips for better results
- Change the second date to see your age on any day.
- Use it for school cut-offs and anniversaries.
Common mistakes to avoid
- Counting a leap-day birthday incorrectly.
- Entering the date in the wrong format.
Please note: Results are estimates for general use. For safety-critical work such as electrical or building projects, check with a qualified professional and local codes. See our Disclaimer.