IP Subnet Calculator (CIDR)
Compute the network and broadcast addresses, host range, subnet mask, and usable host count from CIDR notation (e.g. 192.168.1.0/24). Everything runs in your browser.
Enter e.g. 192.168.1.0/24
FAQ
Why are usable hosts total minus 2?
The first address identifies the network and the last is broadcast. Exceptions: /31 (point-to-point) and /32 (single host) use all addresses.
What is the wildcard mask for?
It's the bitwise inverse of the subnet mask, used in Cisco ACLs and OSPF configuration to match address ranges.
Does it support IPv6?
IPv4 only for now—IPv6's address structure needs a separate tool.
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