How age is calculated
The age in complete years is found by counting how many birthdays have passed between the date of birth and the reference date; the remaining months and days complete the result with calendar precision (accounting for the different number of days in each month and leap years).
Reference date
By default the reference date is today — but you can enter a different date to calculate, for example, the age someone had (or will have) on a specific event, like graduation or retirement.
Other details
Besides the age in years/months/days, the calculator shows the total days and weeks already lived, and how many days remain until the next birthday.
Frequently asked questions
Does this calculator account for leap years?
Yes — the calculation is based on real calendar dates, including the extra day in February during leap years.
Can I calculate age on a future or past date, not today?
Yes, just fill in the reference date field with the date you want.