The entry fees of Kumbhalgarh Fort are as following:

The entry ticket of Kumbhalgarh Fort for an Indian national is INR 5 only and for Foreign Nationals it is INR 100 only.
Digital Cameras are allowed inside the fort without any cost. Fort remains open from Sunrise to Sunset daily throughout the year.

Like Chittorgarh Fort, private vehicles are not allowed on the road inside this fort, so you have to walk a lot to visit the attractions inside the fort area. There are some main attractions like palaces and temples located closed to the main entrance and those can be visited in 2-3 hours, but if you want to see the other temples and attractions like Gole Rao Group of Temples, some Jain Temples, Prithviraj ki Chhatri etc, then it will take about 4-5 hours to explore the entire complex.