Wildcard Mask Calculator

Calculate a wildcard mask, inverse subnet mask, prefix length, and matching address count locally.

CIDR prefix or subnet mask

Wildcard mask (reverse lookup)

—Prefix

—Subnet mask

—Wildcard

—Addresses

ReadyWildcard is the bitwise inverse of the IPv4 subnet mask.

How to use this Wildcard Mask Calculator

Convert subnet masks and CIDR prefixes to IPv4 wildcard masks. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.