29 February comes only in a leap year. This can make age calculations look confusing, but the main idea is simple: compare the full dates on the calendar.
Use the calculator to compare a 29 February birth date with another date.
Two fixed birth dates
An age difference compares two fixed dates. Once both birth dates are known, the gap between them never changes.
If one person was born on 29 February, that extra day is part of the calendar and is included in the calculation.
What happens in a normal year?
A normal year does not have 29 February. A calculator must use one clear rule when it moves a leap-day date into that year.
This site uses the last valid day of the month. So, 29 February can be matched with 28 February in a normal year while counting full years.
Calendar answer and official age
The calculator gives a maths answer. A school, exam board, insurer or government office may have its own rule for a 29 February birthday.
If you are checking an age limit, read the official notice. Do not use a general calculator as the final legal answer.
Useful examples to test
Try these date pairs:
- 29 February 2000 and 28 February 2001
- 29 February 2000 and 1 March 2001
- 29 February 2004 and 29 February 2008
Each example helps you see how full years and extra days are counted.
Total days are easier
The total-day result simply counts every day between the two dates. It includes 29 February whenever that day falls inside the period.
Use the Age Difference Calculator