Subnet Calculator
AvailableCalculate network address, broadcast, usable host range, netmask and host count for any IPv4 or IPv6 CIDR block.
Calculate a subnet
Enter a network to see its range, masks and host counts.
How it works
Pure arithmetic on the address bits, done entirely in your browser — nothing is sent to a server. The prefix length sets how many leading bits identify the network; the remaining bits number the hosts.
Frequently asked questions
How many usable hosts are in a /24?
254. A /24 has 256 addresses, minus the network and broadcast addresses.
What about /31 and /32?
A /31 has two usable addresses on point-to-point links (RFC 3021); a /32 is a single host.