The civil calendar is the calendar, or possibly one of several calendars, used within a country for civil, official, or administrative purposes.[1] The civil calendar is almost always used for general purposes by people and private organizations.
The most widespread civil calendar and de facto international standard is the Gregorian calendar. Although that calendar was first declared by Pope Gregory XIII to be used in Catholic countries in 1582, it has since been adopted, as a matter of convenience, by many secular and non-Christian countries although some countries use other calendars.