Subnet, CIDR and IP calculators for networks

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Subnet and CIDR Calculators

These calculators work on any IPv4 network. CIDR Calculator gives the range and masks of a block, IP Range to CIDR finds the shortest block list, Subnet Mask and Wildcard Mask convert formats, the Visual calculator divides and joins subnets and VLSM plans subnets by host count.

Tools in this group

  • CIDR Calculator — Type a CIDR block such as 192.168.8.0/22 to get its IP range, size, masks and the blocks next to it.
  • Calculate CIDR From IP Range — Enter an IP range such as 192.168.1.10 - 192.168.3.77 to get the shortest list of CIDR blocks that covers it exactly.
  • Subnet Mask Calculator — Find the subnet mask for the hosts or subnets you need, or convert between prefix, dotted mask, wildcard and binary.
  • Visual Subnet Calculator — Enter a network and click Divide or Join to lay out its subnets; each row shows the range, mask, hosts and share.
  • VLSM Calculator — Enter a network and the hosts each subnet needs to get a variable length subnet mask plan with every range and mask.
  • Wildcard Mask Calculator — Enter a subnet mask, prefix or wildcard, or an address range, to get the wildcard mask and the matching ACL lines.