Age Difference Calculator

How far apart are two people in age?

The age difference is measured from the earlier birth date to the later birth date. The result first shows complete years, then complete months, then remaining days.

This is handy for siblings, partners, friends, parents and children, or any two birthdays you want to compare.

Why the number of days is different from years × 365

Real calendars include leap years and months with different lengths. Counting the actual dates gives a better answer than using one fixed number of days per year.

Age difference example

Suppose Person A was born on January 10, 1990 and Person B was born on April 25, 1992. The difference is not simply “about two years.” The calculator counts the complete years, then months, then days between the two birthdays.

It also shows the total number of days between the dates. That can be easier to compare when the birthdays are only weeks or months apart.

What if the birthdays are in different month lengths?

Dates near the end of a month can make hand calculations awkward. January has 31 days, February has 28 or 29, and other months have 30 or 31. The calculator follows the real calendar rather than pretending every month is the same size.

What if both people have the same birthday?

If the full birth dates match, the age difference is zero. If the month and day match but the years are different, the result is a whole number of years.

Age difference versus age today

This page compares two birth dates with each other. To find how old either person is right now, use the main age calculator.