The Juche calendar was introduced in 1997 and is based on Kim Il-sung's date of birth: 15 April 1912. That year is used as Juche 1 and the system works forward from there. There is no Juche 0. The Juche calendar does maintain the Gregorian calendar's traditional months and the number of days in a month. Hence, to calculate the Juche year from a Gregorian year after 1912, simply subtract 1911. The Juche calendar officially replaced the Gregorian calendar as the civil calendar in North Korea on September 9, 1997.
In many instances of non-Korean usage the Juche year is given after the corresponding Gregorian year, i.e. 12 June 2007 (Juche 96). However, most official DPR-Korean sources list the Gregorian year second as in 12 June Juche 96 (2007).