IPv4 CIDR Calculator
Calculate one or many IPv4 subnets from CIDR, subnet mask, or wildcard mask notation.
This tool handles input and primary processing in your browser and is designed not to send the input to QuickKit’s server.
Subnet details
| Address / prefix | — |
|---|---|
| Network address | — |
| Broadcast address | — |
| First host | — |
| Last host | — |
| Netmask | — |
| Wildcard mask | — |
| Total IP addresses | — |
| Usable host count | — |
| Legacy class | — |
| Type | — |
How it works
Enter one address or switch to batch mode for up to 100 lines. CIDR prefixes, subnet masks, and wildcard masks can be mixed. For /31 point-to-point networks, both addresses are usable per RFC 3021; /32 represents one host. The legacy class column is historical context only — CIDR (RFC 4632, BCP 122) replaced classful addressing, so it never affects the calculation. A dotted mask that is valid both ways — only 0.0.0.0 and 255.255.255.255 — is read as a subnet mask, so 0.0.0.0 is /0 and 255.255.255.255 is /32; write the prefix length to state the other reading.