Subnet Masks and CIDR: How Big is Your Network?

An IP address like 192.168.1.50 is useless without its Subnet Mask. The mask tells your computer: "Which part of this address is my neighborhood, and which part is my specific house?"

The Subnet Mask (The Old Way)

A mask like 255.255.255.0 means the first 24 bits are the network ID. Any computer with the same first three numbers is on your local network.

CIDR Notation (The New Way)

Instead of writing out long masks, we use CIDR (Classless Inter-Domain Routing). You've seen this as /24 or /16.

• /32: Exactly one IP address.
• /24: A standard local network (256 IPs).
• /8: A massive network (16.7 million IPs).

Need to calculate a network range? Try our Subnet Calculator for instant results.