Leap year has 366 days, or one more day than an ordinary year. A leap year occurs in every year that can be divided evenly by four, except the years that mark the even hundreds, such as 1500. The only century years that are leap years are those that can be divided evenly by 400, such as 1600 and 2000. Leap years were added to the calendar to make the calendar year nearly the same as the solar year, which is the time it takes for the sun to pass the vernal equinox twice. The extra day is added to the end of February and occurs as February 29 once every four years. See also Year .