The 360 Dates Calendar or 12×30 Calendar is an administrative abstraction overlay to the Gregorian calendar and similar ones, which has 12 months with exactly 30 dates each. Every date covers 1 day at least and 2 days at most. 31 January and 1 March are part of the second month. The 31st days of May, July, August, October and December share a date with the respective 30th day.