A decimal calendar is a calendar which includes

units of time A unit of time is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI) and by extension most of the Western world, is the second, defined as ab ...

based on the decimal system. For example a "decimal month" would consist of a year with 10 months and 36.52422 days per month.

History

Egyptian calendar

The ancient Egyptian calendar consisted of twelve months, each divided into three weeks of ten days, with five

intercalary days Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases. Lunisolar calendars may require intercalations of both days and months. ...

Calendar of Romulus

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. The months of Ianuarius and Februarius were added to the calendar by Numa Pompilius in 700 BCE.

French Republican Calendar

The French Republican Calendar was introduced (along with

decimal time Decimal time is the representation of the time of day using units which are decimally related. This term is often used specifically to refer to the time system used in France for a few years beginning in 1792 during the French Revolution, whi ...

) in 1793, and was similar to the ancient Egyptian calendar. It consisted of twelve months, each divided into three ''décades'' of ten days, with five or six intercalary days called ''

sansculottides The Sansculottides (; also Epagomènes; french: Sans-culottides, Sanculottides, jours complémentaires, jours épagomènes) are holidays following the last month of the year on the French Republican calendar which was used following the French Re ...

''. The calendar was abolished by

Napoleon Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader who ...

on January 1, 1806.

Proposals

The modern

Gregorian calendar The Gregorian calendar is the calendar used in most parts of the world. It was introduced in October 1582 by Pope Gregory XIII as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years dif ...

does not use decimal units of time; however, several proposed calendar systems do. None of these have achieved widespread use.

References