Subnet calculator

IP Address / (CIDR or Netmask)  /  

Classful Network

Class Leading bits Host Address Range Number of Networks Notation CIDR Default Netmask
Class A 0 - 128 /8
Class B 10 - 16384 /16
Class C 110 - 2097152 /24
Class D (multicast) 1110 - not defined not defined
Class E (reserved) 1111 - not defined not defined

Non-routable networks

The folowing addresses are reseved for private networks: to (10/8 prefix) to (172.16 / 12 prefix) to (192.168 / 16 prefix)
Special cases to (LoopBack) to (undeclared hosts) to (Multicast)

This ip address calculator takes IPv4 address and subnet mask or CIDR then calculates and converts to binary ip address, the network address, broadcast address (broadcast), inverse netmask (Cisco wildcard mask), CIDR(Mask Bits), network mask, number of hosts, maximum number of sub-networks, ip range calculator : first and last host address. It is also intended to be a very good educational tool to verify the results and understand the binary values.

Reference : wikipedia: classful network