Adecimal calendar is a calendar which includes units of time based on the decimal system. For example, a "decimal month" would consist of a year with 10 months and 36.52422 days per month.
The ancient Egyptian calendar consisted of twelve months, each divided into three weeks of ten days, with five intercalary days.[1]
The original Roman calendar consisted of ten months; however, the calendar year only lasted 304 days, with 61 days during winter not assigned to any month.[2] The months of Ianuarius and Februarius were added to the calendar by Numa Pompilius in 700 BCE.[2]
The French Republican Calendar was introduced (along with decimal time) in 1793, and was similar to the ancient Egyptian calendar.[3] It consisted of twelve months, each divided into three décades of ten days, with five or six intercalary days called sansculottides.[3] The calendar was abolished by Napoleon on January 1, 1806.[3]
The modern Gregorian calendar does not use decimal units of time; however, several proposed calendar systems do. None of these have achieved widespread use.[example needed]