Subnet Calculator | The Shield IT

📚 CIDR Notation Quick Reference

CIDR (Classless Inter-Domain Routing) notation uses a slash followed by a number to indicate how many bits are used for the network portion of the address.

/24 - Class C network, 256 addresses (254 usable)
/16 - Class B network, 65,536 addresses
/8 - Class A network, 16,777,216 addresses
/30 - Point-to-point link, 4 addresses (2 usable)
/32 - Single host address