Mool Nanakshahi Calendar
Mool Nanakshahi Calendar (NS) combines the Original Nanakshahi Calendar as approved and introduced by SGPC in 1999 (commemorating 300th anniversary of Khalsa Sajna Divas); and also accurately fixes the date for Bandee Shord Divas.
The Sikhs have permanently synchronized the original (Mool) Nanakshahi Calendar with the CE Calendar. This is the only historically, scientifically and Gurbani based Sikh Calendar, free of Bikrami or any other influence. Knowing the history, the timeline of events, evolution, resolutions, and hukamnamas are crucial to knowing the factual Sikh history and preserving the rich culture and heritage. Read a summary of a balanced perspective here.
Mool Nanakshahi Calendar recognizes the adoption event, of 1999 CE, in the Sikh history when SGPC released the first calendar with permanently fixed dates in the Tropical Calendar. Therefore, the calculations of this calendar do not regress back from 1999 CE into the Bikrami era, and accurately fixes historical dates for all time in future. Goes up to year 9999 CE.
Refrence: https://moolnanakshahicalendar.com/