Below is an age difference calculator. Enter the birth dates for two people, and we'll show you their age difference in years, months, and days - plus each person's current age.
Age difference calculator
Using the age difference calculator
To compute the age gap between two people:
- Person 1/Person 2: Enter each person's birthday - order doesn't matter.
- Today Button: Click Today to set a birthday to today (for newborns!).
- Auto-Calculate: Results update instantly as you change dates - no button needed.
The main result shows the age difference in years, months, and days. Below that, you'll see each person's current age displayed side-by-side.
How do you calculate the days?
We start counting on the day of the older person's birthday. We then count every day in between, but we don't count the day of the younger person's birthday.
Basically, if you enter birthdays within one day of each other, it will read as 1 day. If you enter the same birthdays it'll come back as 0 days.
How do leap years affect birthday calculations?
We do count leap years. If the difference in birthdays happens to cross over a February 29 (or more than one!) we will factor it into the calculations.
Of course, generally leap years are abstracted away in the year number, since a year can be 365 or 366 days. In that case the number of years will cover the leap year.
More age and date calculators
Fun, right? We've got a bunch of other time, date, and age calculators for you:
