Local

IP / CIDR calculator

Calculate address ranges and exact counts for IPv4 and IPv6. No scanning and no enormous address lists.

Run the tool

Calculations stay in this browser. Private and documentation networks are accepted and are never submitted to a lookup service.

How to use this tool

  1. Enter an IP and prefix length, such as 192.168.1.10/24 or 2001:db8::/64.
  2. Calculate the normalized network, first and last addresses, and total count.
  3. For IPv4, review the subnet mask and conventional host range. Actual assignment still depends on network configuration.

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Frequently asked questions

Does the calculator scan the network?

No. It performs mathematical calculations without probing addresses or opening connections.

Why does an IPv6 /64 contain so many addresses?

IPv6 addresses have 128 bits. A /64 leaves 64 address bits, giving exactly 2 to the power of 64 addresses. The tool does not enumerate them.

Does the range represent usable public resources?

No. A range describes address space, not whether each address is assigned, routable or available for use.