A standard year is 365 days, but it actually takes the Earth about 365.2422 days to orbit the sun. To keep our calendar in sync with the seasons, we add an extra day every four years (mostly) – February 29th.
The Leap Year Rule
- A year is a leap year if it is divisible by 4.
- However, if it is divisible by 100, it is NOT a leap year...
- ...Unless it is also divisible by 400!
If you were born on February 29th, you technically only have a birthday once every four years. However, legally and mathematically, your age still progresses at the same rate, and next birthdays are often celebrated on February 28th or March 1st.