Subnet Calculator (IPv4 CIDR)
Get the network, broadcast, mask and host range for an IPv4 address and CIDR prefix.
Results update as you type.
About this calculator
A subnet calculator takes an IPv4 address and a CIDR prefix length and works out the network address, broadcast address, subnet mask and the range of usable host addresses. The number of hosts in a /n block is 2^(32−n), of which two (network and broadcast) are reserved.
Frequently asked questions
How many hosts are in a subnet?
A /n subnet has 2^(32−n) addresses, minus two reserved for the network and broadcast. A /24 has 256 addresses and 254 usable hosts.
What is the difference between network and broadcast address?
The network address (all host bits 0) names the subnet; the broadcast address (all host bits 1) reaches every host on it. Neither can be assigned to a device.
What is the difference between network and broadcast address?
The network address (all host bits 0) names the subnet; the broadcast address (all host bits 1) reaches every host on it. Neither can be assigned to a device.
Results are estimates for general guidance only, not financial, medical or tax advice.