So How many Manus are there?

MANU the father of mankind

so now we start to know how many manus are there?

To understand this, we shall first have to go through the basic calculation of time for Lord Brahma. Just like our own division of time, each day of Brahma (known as a Kalpa) is divided into 14 Manvantars (~ our 12 Hours) and each Manvantar is composed of 72 Chatur Yugas ( ~ our 60 Minutes).  

As you can observe from the chart above, the Chatur-yuga and Manvantar periods run into huge time spans. For the smooth functioning of such long intervals of time, each of these has a different set of Gods and Guardians.

For example, the post of Indra passes to the most deserving of the Devas every Manvantar and alongwith him, the groups of Devas, Saptarishis etc. also change posts and so does the Manu.