CIDR Block Cheat Sheet

CIDR SUBNET MASK # OF ADDRESSES
/32 255.255.255.255 1
/31 255.255.255..254 2
/30 255.255.255.252 4
/29 255.255.255.248 8
/28 255.255.255.240 16
/27 255.255.255.224 32
/26 255.255.255.192 64
/25 255.255.255.128 128
/24 255.255.255.0 256
/23 255.255.254.0 512
/22 255.255.252.0 1,024
/21 255.255.248.0 2,048
/20 255.255.240.0 4,096
/19 255.255.224.0 8,192
/18 255.255.192.0 16,384
/17 255.255.128.0 32,768
/16 255.255.0.0 65,536
/15 255.254.0.0 131,072
/14 255.252.0.0 262,144
/13 255.248.0.0 524,288
/12 255.240.0.0 1,048,576
/11 255.224.0.0 2,097,152
/10 255.192.0.0 4,192,304
/9 255.128.0.0 8,388,608
/8 255.0.0.0 16,777,216
/7 254.0.0.0 33,554,432
/6 252.0.0.0 67,108,864
/5 248.0.0.0 134,217,728
/4 240.0.0.0 268,435,456
/3 224.0.0.0 536,870,912
/2 192.0.0.0 1,073,741,824
/1 128.0.0.0 2,147,483,648
/0 0.00.0.0 4,2954,967,296