Subnet, CIDR and IP calculators for networks

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IP, IPv6 and MAC Addresses

These tools deal with single addresses and reference data. The IPv6 pages calculate a subnet, look up a prefix length and generate documentation-safe examples. Others convert an IPv4 address to binary, check private RFC 1918 ranges and find the vendor of a MAC address.

Tools in this group

  • IP to Binary Converter — Type an IPv4 address or 32 bits to convert between dotted decimal and binary, with the place-value table.
  • IPv6 Example Address and Format Checker — Generate documentation-safe IPv6 sample addresses of every type, or paste addresses to validate, compress and expand them.
  • IPv6 Subnet Calculator — Enter an IPv6 address with its prefix to get the network, address range, exact size and how many /64 subnets it holds.
  • IPv6 Subnet Cheat Sheet — Look up any IPv6 prefix length: addresses, /64 networks, /48 sites and its documented use, and see how many of one fit in another.
  • MAC Address Lookup (Vendor / OUI) — Paste a MAC address — or up to 1,000 — to see the registered vendor, the block size, the I/G and U/L bits and every format.
  • Private IP Address Ranges — The RFC 1918 and IPv6 private ranges at a glance, and a checker that tells you whether each address you paste is private.