https://en.wikipedia.org/wiki/Vikram_Samvat
From Wikipedia:
Calendar system
Like the Hebrew and Chinese calendars, the Vikram Samvat is lunisolar. [4] In common years, the year is 354 days long,[12] while a leap month (adhik maas) is added in accordance to the Metonic cycle roughly once every three years (or 7 times in a 19-year cycle) to ensure that festivals and crop-related rituals fall in the appropriate season.[4][5] Early Buddhist communities in India adopted the ancient Hindu calendar, followed by the Vikram Samvat and local Buddhist calendars. Buddhist festivals are still scheduled according to a lunar system.[13]
The Vikram Samvat has two systems. It began in 56 BCE in the southern Hindu calendar system (amaanta) and 57–56 BCE in the northern system (purnimaanta). The Shukla Paksha, when most festivals occur, coincides in both systems.[9][14] The lunisolar Vikram Samvat calendar is 56.7 years ahead of the solar Gregorian calendar; the year 2078 BS begins mid-April 2021 CE, and ends mid-April 2022 CE.
The Rana dynasty of Nepal made the Bikram Sambat the official Hindu calendar in 1901 AD, which began as 1958 BS.[15] The new year in Nepal begins with the first day of the month of Baishakh, which usually falls around 13–15 April in the Gregorian calendar and ends with the last day of the month Chaitra. The first day of the new year is a public holiday in Nepal. Bisket Jatra, an annual carnival in Bhaktapur, is also celebrated on Baishakh 1. In 2007, Nepal Sambat was also recognised as a national calendar alongside Bikram Sambat.
In India, the reformulated Saka calendar is officially used (except for computing dates of the traditional festivals). In the Hindi version of the preamble of the constitution of India, the date of its adoption (26 November 1949) is presented in Vikram Samvat as Margsheersh Shukla Saptami Samvat 2006. A call has been made for the Vikram Samvat to replace the Saka calendar as India's official calendar.[16]
