IP Subnet Calculator

IPv4 Subnet Calculator

Network Class      
IP Address

IPv6 Subnet Calculator

Prefix Length:
IP Address

RelatedBandwidth Calculator | Binary Calculator

A subnet is a way of dividing a network into multiple networks. Routers are used as boundaries between the subnets for traffic exchange. IP addresses are allocated to connected devices in a subnet. An IP address is the combination of two sets of information — a network or routing prefix and the rest field or host identifier.

Normally, the routing prefix is represented with CIDR notation, which is the first address of the subnet, followed with /, and the bit-length of the prefix. For example, means the subnet started with the address of and 24 bits are allocated for the network prefix. Since an IPv4 address has a total of 32 bit. The remaining 8 bits are reserved for hosting addressing. For IPv6, there are a total of 128 bits.

The following are typical subnets for IPv4:

Prefix size Network mask Usable hosts per subnet
Class A
Class B
Class C