Subnet / CIDR Calculator
Calculate IPv4 subnets from CIDR or mask: network, broadcast, host range, wildcard and more.
Divide this network into smaller equal subnets.
Possible subnets: —
| # | Network | Address range | Usable hosts |
|---|
About Subnet / CIDR Calculator
The Subnet Calculator turns an IPv4 address plus a CIDR prefix or subnet mask into every number a network engineer needs: network address, broadcast address, first and last usable host, usable host count, total addresses, wildcard mask and canonical CIDR notation. The prefix and dotted mask stay in sync, so you can enter whichever you have.
It also classifies the address — legacy class A through E and the practical range type: private (RFC 1918), public, loopback, link-local/APIPA, shared CGNAT space, multicast or reserved. A binary breakdown shows the address with network bits visually separated from host bits, the clearest way to understand why a /26 holds 62 hosts.
A subnet split section divides your network into smaller equal subnets: choose a new, longer prefix and get a table of the resulting networks with their address ranges and host counts. All calculation happens instantly in your browser.
How to use Subnet / CIDR Calculator
- Enter an IPv4 address, or click “Load sample” to start with an example.
- Choose the CIDR prefix or the dotted subnet mask — the two stay synchronized.
- Read the results: network, broadcast, first and last usable host, host counts and wildcard mask.
- Study the binary view to see where the network bits end and the host bits begin.
- Pick a longer prefix under “Subnet split” to divide the network into equal subnets.
- Copy any value — or the binary breakdown — with the copy buttons.