Network Tools

CIDR Calculator

Ready
Controls

Input Rules

IPv4 only. Enter CIDR notation or separate IP and prefix. IPv6 is intentionally rejected in this browser-only tool.

Example

10.10.5.20/27

Subnet splitting

By number of subnets or required hosts.

No network0 hosts0 subnets

Calculate a CIDR block to see results.

All calculations run locally in your browser.