Subnet Calculator

The CIDR prefix (like /24 or /16) indicates how many of the 32 bits in an IPv4 address are used for the network portion. A /24 means 24 network bits and 8 host bits, giving 256 addresses (254 usable). Common prefixes: /8 (16 million addresses), /16 (65,536), /24 (256), /28 (16), /30 (4), /32 (1).

/32 is a single host address with no network or broadcast. /31 is a point-to-point link per RFC 3021 with exactly 2 addresses and no traditional broadcast, commonly used for router-to-router connections to save IP space.

No. The same bitwise subnet math applies to all IPv4 addresses. Whether the address is private (10.x.x.x, 172.16-31.x.x, 192.168.x.x) or public only affects routing on the internet, not the subnet calculation itself.

No. This calculator handles IPv4 (32-bit) addresses only. IPv6 uses 128-bit addresses with hexadecimal notation and requires a different subnet calculator.

The wildcard mask is the inverse of the subnet mask (each bit flipped). For a /24 subnet mask 255.255.255.0, the wildcard mask is 0.0.0.255. Wildcard masks are used in Cisco ACLs and OSPF configurations to specify which address bits to match.

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