A common year is a year that is common calendar year. It has exactly 365 days and so is not a leap year. More generally it is a calendar year without intercalation.

A common year of 365 days has exactly 52 weeks and one day, so consequently the next new year is one day of the week later.

For example 2007, which is a common year, began on Monday, therefore 2008 began on a Tuesday.

In the Gregorian calendar, 303 of every 400 years are common years. By comparison, in the Julian Calendar, 300 out of every 400 years were common years (3 out of 4 years).