🧮 Subnet Mask Cheat Sheet

Complete IPv4 subnet mask, CIDR prefix, wildcard mask, and usable host reference table.

📊 IPv4 Reference
🔍
Ctrl+K
MaskWildcardCIDRHostsClass
0.0.0.0255.255.255.255/04,294,967,294Entire Internet
128.0.0.0127.255.255.255/12,147,483,646128 /8 networks
192.0.0.063.255.255.255/21,073,741,82264 /8 networks
224.0.0.031.255.255.255/3536,870,91032 /8 networks
240.0.0.015.255.255.255/4268,435,45416 /8 networks
248.0.0.07.255.255.255/5134,217,7268 /8 networks
252.0.0.03.255.255.255/667,108,8624 /8 networks
254.0.0.01.255.255.255/733,554,4302 /8 networks
255.0.0.00.255.255.255/816,777,214Class A
255.128.0.00.127.255.255/98,388,606128 /16 networks
255.192.0.00.63.255.255/104,194,30264 /16 networks
255.224.0.00.31.255.255/112,097,15032 /16 networks
255.240.0.00.15.255.255/121,048,57416 /16 networks
255.248.0.00.7.255.255/13524,2868 /16 networks
255.252.0.00.3.255.255/14262,1424 /16 networks
255.254.0.00.1.255.255/15131,0702 /16 networks
255.255.0.00.0.255.255/1665,534Class B
255.255.128.00.0.127.255/1732,766128 /24 networks
255.255.192.00.0.63.255/1816,38264 /24 networks
255.255.224.00.0.31.255/198,19032 /24 networks
255.255.240.00.0.15.255/204,09416 /24 networks
255.255.248.00.0.7.255/212,0468 /24 networks
255.255.252.00.0.3.255/221,0224 /24 networks
255.255.254.00.0.1.255/235102 /24 networks
255.255.255.00.0.0.255/24254Class C
255.255.255.1280.0.0.127/25126128 hosts
255.255.255.1920.0.0.63/266264 hosts
255.255.255.2240.0.0.31/273032 hosts
255.255.255.2400.0.0.15/281416 hosts
255.255.255.2480.0.0.7/2968 hosts
255.255.255.2520.0.0.3/3024 hosts
255.255.255.2540.0.0.1/3102 hosts (RFC 3021)
255.255.255.2550.0.0.0/3211 host

📘 Class A

/8 = 255.0.0.0
16,777,214 hosts
1.0.0.0 — 126.255.255.255

📙 Class B

/16 = 255.255.0.0
65,534 hosts
128.0.0.0 — 191.255.255.255

📕 Class C

/24 = 255.255.255.0
254 hosts
192.0.0.0 — 223.255.255.255