IPv4 Subnet Calculator
Work out the network, broadcast, host range and mask from an IP and CIDR.
Learn subnetting in the CCNA course →
Frequently asked questions
How do I calculate a subnet?
From an IP and its mask (or /CIDR) you AND them to get the network address; the broadcast is the network with all host bits set. The hosts in between are usable.
How many hosts are in a /24?
A /24 has 256 addresses and 254 usable hosts (the network and broadcast addresses are reserved).