IP CIDR Calculator

About CIDR Notation

CIDR (Classless Inter-Domain Routing) notation is a compact method for specifying IP addresses and their associated routing prefix. It combines the network address with the prefix length, written as: address/prefix-length.

Common CIDR blocks:

• /24 - 256 addresses (typical home network)
• /16 - 65,536 addresses (medium organization)
• /8 - 16,777,216 addresses (large network)