How it works
Enter a date of birth to get an exact calendar age in completed years, months and days, the way age is normally stated on forms and documents.
The calculator also shows the total number of months, weeks and days lived, the weekday you were born on, and how many days remain until your next birthday. Change the "age on" date to find someone's age on a past or future date.
People born on February 29 are treated as having their birthday on March 1 in non-leap years, which is the rule used for legal age in many places.
Formula
Age = completed years, then completed months, then remaining days between the birth date and the target date.
Questions people ask
How is age in months and days counted?
Whole years are counted first, then whole months, then the leftover days. If the day of the month has not been reached yet, a month is borrowed and the number of days in the previous month is added.
Why does my total days figure differ from years × 365?
Total days counts every real calendar day, including the extra day in each leap year you have lived through.
How are February 29 birthdays handled?
In years without a February 29, the next birthday is shown as March 1. Some people celebrate on February 28 instead; the legal convention varies by country.