Free IP Subnet Calculator

Find network address, broadcast, and usable host range from an IP and subnet mask.

Subnetting divides a larger network into smaller segments — the CIDR notation (e.g. /24) indicates how many bits are reserved for the network portion, with the remaining bits available for host addresses. A /24 gives 256 total addresses (254 usable, since the first is the network address and the last is broadcast).

Worked Example

Example: 192.168.1.100/24 → Network: 192.168.1.0, Broadcast: 192.168.1.255, Usable range: 192.168.1.1 – 192.168.1.254, Total hosts: 254.

Formula / Method

Network Address = IP AND Subnet Mask
Broadcast Address = Network Address OR (NOT Subnet Mask)
Usable Hosts = 2^(32-CIDR) − 2

Worked Example

Example: 192.168.1.100/24 → Network: 192.168.1.0, Broadcast: 192.168.1.255, Usable range: 192.168.1.1 – 192.168.1.254, Total hosts: 254.

Formula / Method

Network Address = IP AND Subnet Mask
Broadcast Address = Network Address OR (NOT Subnet Mask)
Usable Hosts = 2^(32-CIDR) − 2