GLOBAL IP LOOKUP

FREE NETWORK TOOL

IPv4 subnet calculator

Enter an IPv4 address with a CIDR prefix to calculate its subnet mask, network and broadcast addresses, usable host range and address capacity.

Example: 10.20.30.40/20

CALCULATED NETWORK

192.168.1.0/24

IPv4
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255
Network address
192.168.1.0
Broadcast address
192.168.1.255
First usable address
192.168.1.1
Last usable address
192.168.1.254
Total addresses
256
Usable addresses
254

What CIDR notation means

The number after the slash shows how many leading bits identify the network. A /24 leaves eight host bits and contains 256 total IPv4 addresses. A shorter prefix creates a larger network.

Network and broadcast addresses

The network address is the first address in a traditional IPv4 subnet, while the broadcast address is the last. For prefixes up to /30, those two addresses are normally excluded from the usable host count.

Special /31 and /32 networks

A /31 contains two addresses and is commonly used on point-to-point links. A /32 represents one host route. The calculator reports both addresses in a /31 as usable and the single /32 address as its own range.