CIDR Notation Cheat Sheet — Subnet Masks & Host Counts
Complete CIDR reference table: every prefix from /8 to /32 with subnet mask, total addresses, usable hosts, and common use cases.
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Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation expresses an IP address and its network prefix in the form 192.168.1.0/24. The number after the slash tells you how many bits identify the network — the remaining bits are available for host addresses.
How many hosts does a /24 subnet have?
A /24 subnet has 256 total addresses (2^8). Two are reserved: one for the network address and one for broadcast. That leaves 254 usable host addresses.
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