Subnet Cheat Sheet

Sub Addresses Hosts Netmask Amount of a Class C
/ 30 4 2 255.255.255.252 1 / 64
/ 29 8 6 255.255.255.248 1 / 32
/ 28 16 14 255.255.255.240 1 / 16
/ 27 32 30 255.255.255.224 1 / 8
/ 26 64 62 255.255.255.192 1 / 4
/ 25 128 126 255.255.255.128 1 / 2
/ 24 256 254 255.255.255.0 1
/ 23 512 510 255.255.254.0 2
/ 22 1024 1022 255.255.252.0 4
/ 21 2048 2046 255.255.248.0 8
/ 20 4096 4094 255.255.240.0 16
/ 19 8192 8190 255.255.224.0 32
/ 18 16384 16382 255.255.192.0 64
/ 17 32768 32766 255.255.128.0 128
/ 16 65536 65534 255.255.0.0 256