Nearly every four years, we add an extra day to the calendar in the form of February 29, also known as Leap Day. Put simply, these additional 24 hours are built into the calendar to ensure that it stays in line with the Earth's movement around the Sun.

How does it work if your born on leap day?

If you are born on a leap day, you don't always celebrate your actual birthday because that day (February 29) occurs only every four years. If you are born on a leap day, you'll usually celebrate your birthday on February 28 or March 1 and use one of those dates for identification and important documents.

What's another word for leap day?

A leap year is a year that has an extra day—366 days, with February 29 as the extra day. It has another name in English: bissextile year (and leap day is also known as bissextile day).