Subnet Mask Cheat Sheet

CIDR Mask Addresses Hosts
/30 255.255.255.252 4 2
/29 255.255.255.248 8 6
/28 255.255.255.240 16 14
/27 255.255.255.224 32 30
/26 255.255.255.192 64 62
/25 255.255.255.128 128 126
/24 255.255.255.0 256 254
/23 255.255.254.0 512 510
/22 255.255.252.0 1024 1022
/21 255.255.248.0 2048 2046
/20 255.255.240 4096 4094