how many days in a year?
How many Days are in a Year? Days in a year calculation Gregorian calendar year. One calendar common year has 365 days 1 common year = 365 days. One calendar leap year has 366 days 1 leap year = 366 days. Leap year occurs every 4 years except for years that are divisible by 100 and not divisible by 400. So the mean length of the Gregorian calendar year is