The International Fixed Calendar (also known as the Cotsworth plan, the Cotsworth calendar, the Eastman plan or the Yearal)[1] was a proposed reform of the Gregorian calendar designed by Moses B. Cotsworth, first presented in 1902.[2] The International Fixed Calendar divides the year into 13 months of 28 days each. A type of perennial calendar, every date is fixed to the same weekday every year. Though it was never officially adopted at the country level, the entrepreneur George Eastman instituted its use at the Eastman Kodak Company in 1928, where it was used until 1989.[3] While it is sometimes described as the 13-month calendar or the equal-month calendar, various alternative calendar designs share these features.
