To be a leap year, the year number must be divisible by four – except for end-of-century years, which must be divisible by 400. This means that the year 2000 was a leap year, although 1900 was not. 2020, 2024 and 2028 are all leap years.

What is a leap year and when does it occur?

Leap years are years where an extra, or intercalary, day is added to the end of the shortest month, February. The intercalary day, February 29, is commonly referred to as leap day. Leap years have 366 days instead of the usual 365 days and occur almost every four years. Leap years have 366 instead of 365 days.

Why is leap year every 4 years?

It takes approximately 365.25 days for Earth to orbit the Sun — a solar year. We usually round the days in a calendar year to 365. To make up for the missing partial day, we add one day to our calendar approximately every four years. That is a leap year.