IP Subnet Calculator

Subnetting is the practice of dividing a network into two or more smaller networks. It increases routing efficiency and enhances network security. However, calculating the precise range of IP addresses, masks, and broadcast addresses manually is error-prone.

What is CIDR Notation?

CIDR (Classless Inter-Domain Routing) is the modern standard for IP addressing. It uses a flexible suffix (e.g., `/24`) to indicate how many bits of the IP address represent the network vs. the host.
For example, in `192.168.1.0/24`:

• The IP address is `192.168.1.0`.
• The `/24` prefix means the first 24 bits (3 octets) identify the network.
• The remaining 8 bits are used for host addresses (2^8 = 256 addresses).

Common Subnets Cheat Sheet