ShellYard
Last reviewed against v0.9.0 source: internal/tools/

Subnet calculator

CIDR / VLSM / split / summarize. IPv4 and IPv6. Usable-host count, broadcast, network rows.

IPv4 and IPv6 subnet math:

  • CIDR breakdown — network, broadcast, first / last usable, mask, wildcard, usable host count
  • VLSM split — divide a parent network into N variable-sized children
  • Summarize — fold a set of subnets into the smallest covering CIDR