The Nanakshahi (Punjabi: ਨਾਨਕਸ਼ਾਹੀ, nānakashāhī) calendar is a tropical solar calendar which is used in Sikhism and is based on the 'Barah Maha' (Punjabi: ਬਾਰਹ ਮਾਹਾ). Barah Maha was composed by the Sikh Gurus and translates as the "Twelve Months". It is a poem reflecting the changes in nature which are conveyed in the twelve-month cycle of the Year. The year begins with the month of Chet, with 1 Chet corresponding to 14 March. The first year of the Nanakshahi Calendar starts in 1469 CE: the year of the birth of Guru Nanak Dev.
The Nanakshahi Calendar is named after the founder of the Sikh religion, Guru Nanak Dev.