Network tools
Subnet and CIDR calculators for IPv4 and IPv6, IP lookups and bandwidth maths. Calculators run in your browser.
IPv4
- Subnet calculatorNetwork, broadcast, usable hosts and netmask for any IP and prefix.
- CIDR to IP rangeFirst and last address of a CIDR block, and how many it holds.
- IP range to CIDRThe fewest CIDR blocks that cover a first–last address range exactly.
- Netmask to CIDRNetmask, prefix length and wildcard mask: type one, get all three.
- CIDR aggregatorMerge a list of blocks, ranges and addresses into the fewest CIDRs.
- IP to decimalAn IPv4 address as a number, in hex, octal and binary, and back.
- Subnet splitterSplit an IPv4 block into equal subnets by size, count or hosts.
- VLSM calculatorFit subnets of different sizes into one block, largest first.
- Wildcard maskWhat a Cisco wildcard mask matches, and ACL lines for any CIDR or range.
- Subnet cheat sheetEvery IPv4 prefix with its netmask and size, plus common IPv6 prefixes.
IPv6
- IPv6 subnet calculatorNetwork, first and last address, and /64 count for an IPv6 prefix.
- IPv6 CIDR to rangeFirst and last address of an IPv6 prefix, and how many /64s it holds.
- IPv6 range to CIDRThe fewest IPv6 prefixes that cover a first–last address range exactly.
- IPv6 expand and compressFull and RFC 5952 short forms of IPv6 addresses, one or a whole list.
- IPv6 CIDR aggregatorMerge a list of IPv6 prefixes and ranges into the fewest prefixes.
- IPv6 subnet splitterSplit an IPv6 prefix into equal subnets, like a /48 into /64s.
- IPv4 to IPv6IPv4-mapped, 6to4 and NAT64 forms, and the IPv4 hidden inside an IPv6 address.
- MAC to IPv6 (EUI-64)The EUI-64 interface ID, link-local and SLAAC address for a MAC, and back.
- IPv6 to decimalAn IPv6 address as a 128-bit number, in hex and binary, and back.
- IPv6 ULA generatorA random fd00::/8 private prefix for your network, or check one you have.
IPv4 and IPv6
- IP type checkerPrivate, public, reserved or multicast? Every special-purpose range, with its RFC.
- IP in range checkTest which addresses fall inside a list of CIDR blocks and ranges.
- CIDR overlap checkFind overlapping blocks in a list and get a clean list without them.
- CIDR excludeRemove blocks from a range and get the CIDRs left, for WireGuard AllowedIPs.
- CIDR to IP listEvery address in a block or range, one per line, ready to copy.
- IP extractor and sorterPull every IP address out of logs, headers or HTML, then sort and count.
- Allowlist formatterTurn an IP list into Postfix, nginx, firewall, AWS or SPF rules.
- Reverse DNS zonesPTR names, the in-addr.arpa or ip6.arpa zones for a network, and a zone file.
- Random IP generatorRandom addresses from a CIDR block or range, with no repeats.
Lookups
Bandwidth
No tools match.