How many types of calendar are there?

There are actually seven or more calendars around the world and their study is very interesting. Although the Gregorian calendar is the one most widely in use, certainly in the western world, there are also its predecessor, the Julian Calendar, the Hebrew Calendar., the Hijri Calendar, the Iranian Muslim Calendar, the Buddhist Calendar, the Vikram Samvat, Shaka Samvat, and Kali Yuga calendar, the Japanese Calendar and Chinese Calendar. the Zodiac calendar is one that many find fascinating. However, the Gregorian is the one that overcame the solstice and equinox problem with measuring time passing.