Network utility

IPv4 CIDR Calculator

Calculate a normalized IPv4 network, masks, address range, broadcast address, and usable hosts.

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Local processing

The address is calculated in this browser. This tool sends no calculation request.

Example: 10.20.30.40/20 . Prefixes from /0 through /32 are supported.

Normalized CIDR —
Subnet mask —
Wildcard mask —
Network address —
Broadcast address —
Address count —
First usable —
Last usable —
Usable hosts —

How to use it

  1. Enter an IPv4 address followed by a slash prefix.
  2. Select Calculate to normalize the network.
  3. Use the range and mask values when planning or checking a subnet.

Special prefixes

A /31 has two usable point-to-point addresses. A /32 identifies one host. Other subnets reserve network and broadcast addresses.

Read IPv4 CIDR and subnet ranges for worked examples.