Network range, netmask, hosts.. CIDR Calculator is a free online tool from the ToolsRift Developer Tools collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Enter a CIDR like 192.168.1.10/24 and the tool computes the network and broadcast addresses, netmask, wildcard mask, first and last usable host, and host count.
It is the number of leading 1-bits in the netmask. /24 means the first 24 bits are the network and the last 8 bits address hosts.
The network and broadcast addresses are reserved, so a /24 has 256 addresses but only 254 usable hosts.
/32 is a single host and /31 is a two-address point-to-point link, so no separate usable-host range is reported.