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CIDR Subnet Calculator

Enter an IPv4 CIDR block to get the network, broadcast, mask, host range and usable host count.

  • Network address192.168.1.0/24
  • Broadcast address192.168.1.255
  • Subnet mask255.255.255.0
  • Wildcard mask0.0.0.255
  • Usable host range192.168.1.1 – 192.168.1.254
  • Usable hosts254
  • Total addresses256

How to use it

  1. Enter a CIDR block An IPv4 address with a prefix, like 192.168.1.0/24.
  2. Read the network details Network, broadcast and mask are computed.
  3. Check the host range See the first and last usable host and the count.

Examples

/24 254 hosts
/30 2 hosts

About this tool

Subnetting trips up even experienced engineers, because it all comes down to binary masks. This calculator takes an IPv4 CIDR block and works out the network address, broadcast address, subnet mask and wildcard mask in one go.

It also gives the usable host range and host count, correctly handling the edge cases at /31 and /32. Whether you’re planning a network or studying for a certification, it removes the manual binary arithmetic — all in your browser.

Frequently asked questions

How are usable hosts counted?

For prefixes up to /30, the network and broadcast addresses are excluded, so usable hosts is two fewer than the total. /31 and /32 are handled as special cases.

Does it support IPv6?

This calculator covers IPv4 CIDR blocks, which are by far the most common for subnetting questions.

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Updated June 13, 2026