Vira Nirvan Samvat :

The Vira Nirvana Samvat (period), according to the calendar, started on October 7, 527 BCE.
It honours Lord Mahavir, the 24th Jain Tirthankara, who attained Nirvana on this day.
The earliest system of chronological reckoning currently in use in India is this one.

Vikram Samvat :

In Gujrat, to determine auspicious days and holy schedules for every religion, fairs, occasions, and festivals, Gujaratis utilise the Vikram Samvat calendar. The first day after the new moon in the autumnal month of Kartak—one day after Diwali—marks the start of the new year.

The Gregorian calendar is 57 years behind the Vikram Samvat year, and it is 56 years behind from January to April.
Following his victory against the Shakas in 56 BCE, the monarch Vikramaditya of Ujjain established the Vikrama Samvat calendar.It makes use of a solar sidereal year and splits it into 12 lunar months, each of which has a length of 29 days, 12 hours, and 44 minutes. A whole lunar year of 354 days, 8 hours, and 48 minutes

Saka Samvat :

The Saka Samvat or Era began in B.C. 78, under the reign of Saka Kshatrap Nahpan.
Christian year is created by adding up the Saka year by 78.
for instance, Saka 1752 + 78 Equals A.D. 1830.