← /tools / cidr-calculator
IPv4 and IPv6 CIDR breakdown with scope classification (private / loopback / CGNAT / reserved). Switch tabs for equal-size subnet splitting, VLSM allocation by host count, supernet aggregation, and range → minimal CIDR set. All calculations run in your browser — nothing is transmitted to any server.
Runs entirely in your browser — nothing is uploaded and no network request fires on use.