Network tool

Calculate a subnet mask

A mask distinguishes the network part from the host part of an IPv4 address.

Subnet mask
255.255.255.0
Longueur du préfixe
24
Représentation binaire
11111111.11111111.11111111.00000000

Calculation performed locally in your browser.

Example

The mask 255.255.255.0 corresponds to /24.

Planning

Suitable subnets limit the waste of addresses and structure a network.

Validation

The tool rejects non-continuous masks, for example with bits of 1 after zeros.

To be explored next

All Tools

Tool and documentation verified on July 15, 2026.