How many network IDs are there in a Class B IP address?

In a class B IP address, the first two bytes represent the network.

The first two bits are 1 and 0, which means that there are 214 (10 000000 00000000 to 10 111111 11111111) network possibilities, which is 16,384 possible networks. The networks available in class B are therefore networks going from 128.0.0.0 to 191.255.0.0.

The two bytes to the left represent the computers on the network. The network can therefore contain a number of computers equal to:

216-21 = 65,534 computers.