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 0.0.0.0 - 127.255.255.255 128 /8 255.0.0.0
Class B 10 128.0.0.0 - 191.255.255.255 16384 /16 255.255.0.0
Class C 110 192.0.0.0 - 223.255.255.255 2097152 /24 255.255.255.0
Class D (multicast) 1110 224.0.0.0 - 239.255.255.255 not defined not defined
Class E (reserved) 1111 240.0.0.0 - 255.255.255.255 not defined not defined


Non-routable networks


The folowing addresses are reseved for private networks:

10.0.0.0 to 10.255.255.255 (10/8 prefix)
172.16.0.0 to 172.31.255.255 (172.16 / 12 prefix)
192.168.0.0 to 192.168.255.255 (192.168 / 16 prefix)
Special cases
127.0.0.0 to 127.255.255.255 (LoopBack)
169.254.0.0 to 169.254.255.255 (undeclared hosts)
224.0.0.0 to 239.255.255.255 (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