Calculate IP subnet details

Enter an address with a prefix such as 192.168.1.10/26, or an address and mask. The details update as you type, and you can split the network into equal smaller subnets.

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How to use

Enter an address with prefix (192.168.1.10/26) or a mask.
Read the details; split into smaller subnets if needed.

Worked example

192.168.1.10/26 is in network 192.168.1.0, broadcast 192.168.1.63, hosts .1 to .62 (62 usable), mask 255.255.255.192.

Supported formats and limits

Input	IP/prefix or IP and mask
Output	Subnet details, split table
Engine	BigInt address arithmetic

Limitations

/31 and /32 follow RFC 3021 conventions (no broadcast address).

Questions

How many usable hosts does a subnet have?

For IPv4, the address count minus the network and broadcast addresses. 192.168.1.10/26 is in network 192.168.1.0 with broadcast 192.168.1.63, leaving 62 usable hosts. /31 and /32 follow RFC 3021 and have no broadcast address.

Does it work with IPv6?

Yes. IPv6 has no broadcast address, so the tool shows the network, the first and last address and the size. Addresses are written in the compressed form from RFC 5952.

Guides

IPv4 subnetting step by step: CIDR, masks and usable hosts

Privacy

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