How to Calculate Age From a Birth Date: Years, Months and Days
Calendar age, leap years and working out your age on a specific date.
Calculating age looks simple but leap years and month lengths can give surprising results. The right way is to split the span into whole years, remaining months and remaining days.
Step by step
Take the year difference and subtract one if the birthday has not come yet this year. Then find the leftover months and days. Someone born on 15 March 1990 is 36 years, 7 months and 10 days old on 25 October 2026.
Born on 29 February
People born on a leap day are legally treated as turning a year older on 28 February or 1 March in non-leap years, depending on the country.
Age on a given date
For a licence, retirement or school application you may need your age on a future date. Type that day into the “Age at date” field.
- Age can also be expressed in total days; use the Date Difference tool for that.
- Age by the lunar Hijri calendar is about 3% larger because its year is shorter.
Use the Age Calculator to see years, months and days instantly.