128 64 32 16 8 4 2 1
1 128 10000000
2 192 11000000
3 224 11100000
4 240 11110000
5 248 11111000
6 252 11111100
7 254 11111110
8 255 11111111
CIRD to DDN
/12 8.4.0.0 255.240.0.0
/20 8.8.4.0 255.255.240.0
/28 8.8.8.4 255.255.255.240
Private IP ranges
Class Range of IPs Default CIRD
A 10.0.0.1 - 10.255.255.254 /8
B 172.16.0.1 - 172.31.255.254 /16
C 192.168.0.1 - 192.168.255.254 /24
CIDR Subnet Mask Total IPs
/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 1024
/21 255.255.248.0 2048
/20 255.255.240.0 4096
/19 255.255.224.0 8192
/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 4,194,304
/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