Subnet Calculator

How to calculate a subnet

1. Type an IPv4 address with its prefix, such as 192.168.1.10/24, or with a netmask, such as 10.0.0.1 255.255.0.0.
2. The network and prefix appear with the number of usable hosts.
3. The table lists the network, broadcast, host range, netmask and wildcard mask.

Frequently asked questions

Why are two addresses not usable?

The first address names the network and the last is the broadcast address. /31 and /32 networks are the exception and use every address.

What does /24 mean?

The first 24 bits are the network part, leaving 8 bits for hosts: 256 addresses, 254 of them usable. The netmask is 255.255.255.0.

What is a wildcard mask?

The netmask with its bits flipped, such as 0.0.0.255 for /24. Cisco access lists and OSPF use it.