Plan and verify IP networks. The subnet calculator turns an IP address and a CIDR prefix or netmask into the full picture, entirely in your browser. Nothing you enter leaves your device.
Answers appear as you type, with every calculation done locally in your browser.
The subnet calculator turns an IP address and a CIDR prefix or netmask into the network address, broadcast address, usable host range, and binary breakdown. Use it to plan address space or double-check router and firewall settings. Every calculation runs in your browser.
No. Subnetting divides an address range into smaller blocks. Segmentation is the security practice of separating systems so that a compromise in one area cannot spread freely to another. Good segmentation combines subnets with firewall rules and access controls, and it is one of the first things auditors test.
When a regulator, customer, or cyber insurer asks for independent evidence, after major changes such as a merger or cloud migration, or when you are not sure your segmentation and firewall rules work as intended. A network security audit tests your internal and external defenses and tells you what to fix first.
