CIDR Conversion Table

CIDR prefix length

Dotted Decimal Netmask

Hexidecimal Netmask

Inverse Netmask

Binary

Number of Classfull Networks

Number of Usable IPs

/1128.0.0.080 00 00 00127.255.255.2551000 0000 0000 0000 0000 0000 0000 0000128 As2,147,483,646
/2192.0.0.0C0 00 00 0063.255.255.2551100 0000 0000 0000 0000 0000 0000 000064 As1,073,741,822
/3224.0.0.0E0 00 00 0031.255.255.2551110 0000 0000 0000 0000 0000 0000 000032 As536,870,910
/4240.0.0.0F0 00 00 0015.255.255.2551111 0000 0000 0000 0000 0000 0000 000016 As268,435,454
/5248.0.0.0F8 00 00 007.255.255.2551111 1000 0000 0000 0000 0000 0000 00008 As134,217,726
/6252.0.0.0FC 00 00 003.255.255.2551111 1100 0000 0000 0000 0000 0000 00004 As67,108,862
/7254.0.0.0FE 00 00 001.255.255.2551111 1110 0000 0000 0000 0000 0000 00002 As33,554,430
/8255.0.0.0FF 00 00 000.255.255.2551111 1111 0000 0000 0000 0000 0000 00001 A or 256 Bs16,777,214
/9255.128.0.0FF 80 00 000.127.255.2551111 1111 1000 0000 0000 0000 0000 0000128 Bs8,388,606
/10255.192.0.0FF C0 00 000.63.255.2551111 1111 1100 0000 0000 0000 0000 000064 Bs4,194,302
/11255.224.0.0FF E0 00 000.31.255.2551111 1111 1110 0000 0000 0000 0000 000032 Bs2,097,150
/12255.240.0.0FF F0 00 000.15.255.2551111 1111 1111 0000 0000 0000 0000 000016 Bs1,048,574
/13255.248.0.0FF F8 00 000.7.255.2551111 1111 1111 1000 0000 0000 0000 00008 Bs524,286
/14255.252.0.0FF FC 00 000.3.255.2551111 1111 1111 1100 0000 0000 0000 00004 Bs262,142
/15255.254.0.0FF FE 00 000.1.255.2551111 1111 1111 1110 0000 0000 0000 00002 Bs131,070
/16255.255.0.0FF FF 00 000.0.255.2551111 1111 1111 1111 0000 0000 0000 00001 B or 256 Cs65,534
/17255.255.128.0FF FF 80 000.0.127.2551111 1111 1111 1111 1000 0000 0000 0000128 Cs32,766
/18255.255.192.0FF FF C0 000.0.63.2551111 1111 1111 1111 1100 0000 0000 000064 Cs16,382
/19255.255.224.0FF FF E0 000.0.31.2551111 1111 1111 1111 1110 0000 0000 000032 Cs8,190
/20255.255.240.0FF FF F0 000.0.15.2551111 1111 1111 1111 1111 0000 0000 000016 Cs4,094
/21255.255.248.0FF FF F8 000.0.7.2551111 1111 1111 1111 1111 1000 0000 00008 Cs2,046
/22255.255.252.0FF FF FC 000.0.3.2551111 1111 1111 1111 1111 1100 0000 00004 Cs1,022
/23255.255.254.0FF FF FE 000.0.1.2551111 1111 1111 1111 1111 1110 0000 00002 Cs510
/24255.255.255.0FF FF FF 000.0.0.2551111 1111 1111 1111 1111 1111 0000 00001 C254
/25255.255.255.128FF FF FF 800.0.0.1271111 1111 1111 1111 1111 1111 1000 00001/2 C126
/26255.255.255.192FF FF FF C00.0.0.631111 1111 1111 1111 1111 1111 1100 00001/4 C62
/27255.255.255.224FF FF FF E00.0.0.311111 1111 1111 1111 1111 1111 1110 00001/8 C30
/28255.255.255.240FF FF FF F00.0.0.151111 1111 1111 1111 1111 1111 1111 00001/16 C14
/29255.255.255.248FF FF FF F80.0.0.71111 1111 1111 1111 1111 1111 1111 10001/32 C6
/30255.255.255.252FF FF FF FC0.0.0.31111 1111 1111 1111 1111 1111 1111 11001/64 C2
/31255.255.255.254FF FF FF FE0.0.0.11111 1111 1111 1111 1111 1111 1111 11101/128 C0
/32255.255.255.255FF FF FF FF0.0.0.01111 1111 1111 1111 1111 1111 1111 11111/256 C1
Reserved Network Numbers
ClassStartEndNumber of IPsComment
  A  10.0.0.0  10.255.255.255  16,777,216  A single Class A network number
  B  172.16.0.0  172.31.255.2551,048,544  16 contiguous Class B network numbers
  C  192.168.0.0    192.168.255.255  65,534  256 contiguous Class C network numbers