Subnet Calculator
Calculate network, broadcast, host range, and mask details from CIDR.
Subnet Calculator derives the network address, broadcast address, usable host range, and subnet mask from CIDR input. CIDR notation combines an IP address with a prefix length, such as /24, where the prefix marks how many leading bits identify the network rather than individual hosts. The network address is the first address in the block, the broadcast address is the all-hosts address in IPv4, and the usable range excludes addresses reserved for network and broadcast roles. Subnet masks express the same boundary in dotted decimal form. This tool is useful for network planning and troubleshooting because it makes address boundaries explicit, but production changes should still be checked against router, cloud-provider, DHCP, and firewall configuration.