About Subnet Math

Subnet Math is a set of free subnetting tools: give it an address and a prefix length and it returns the network address, broadcast address, host range, mask and wildcard, worked through in binary.

The math follows the IPv4 and IPv6 addressing standards, including the /31 and /32 special cases from RFC 3021. It describes how an address block divides up; it doesn't design or secure anyone's network.

Spotted a mistake? Email hello@subnetmath.com.