Netmask CIDR conversion

Netmask Binary CIDR Notes

255.255.255.255 11111111.11111111.11111111.11111111 /32 1 useable
255.255.255.254 11111111.11111111.11111111.11111110 /31 0 useable
255.255.255.252 11111111.11111111.11111111.11111100 /30 2 useable
255.255.255.248 11111111.11111111.11111111.11111000 /29 6 useable
255.255.255.240 11111111.11111111.11111111.11110000 /28 14 useable
255.255.255.224 11111111.11111111.11111111.11100000 /27 30 useable
255.255.255.192 11111111.11111111.11111111.11000000 /26 62 useable
255.255.255.128 11111111.11111111.11111111.10000000 /25 126 useable

255.255.255.0 11111111.11111111.11111111.00000000 /24 class C

255.255.254.0 11111111.11111111.11111110.00000000 /23
255.255.252.0 11111111.11111111.11111100.00000000 /22
255.255.248.0 11111111.11111111.11111000.00000000 /21
255.255.240.0 11111111.11111111.11110000.00000000 /20
255.255.224.0 11111111.11111111.11100000.00000000 /19
255.255.192.0 11111111.11111111.11000000.00000000 /18
255.255.128.0 11111111.11111111.10000000.00000000 /17
255.255.0.0 11111111.11111111.00000000.00000000 /16 class B

255.254.0.0 11111111.11111110.00000000.00000000 /15
255.252.0.0 11111111.11111100.00000000.00000000 /14
255.248.0.0 11111111.11111000.00000000.00000000 /13
255.240.0.0 11111111.11110000.00000000.00000000 /12
255.224.0.0 11111111.11100000.00000000.00000000 /11
255.192.0.0 11111111.11000000.00000000.00000000 /10
255.128.0.0 11111111.10000000.00000000.00000000 /9
255.0.0.0 11111111.00000000.00000000.00000000 /8 class A

254.0.0.0 11111110.00000000.00000000.00000000 /7
252.0.0.0 11111100.00000000.00000000.00000000 /6
248.0.0.0 11111000.00000000.00000000.00000000 /5
240.0.0.0 11110000.00000000.00000000.00000000 /4
224.0.0.0 11100000.00000000.00000000.00000000 /3
192.0.0.0 11000000.00000000.00000000.00000000 /2
128.0.0.0 10000000.00000000.00000000.00000000 /1
0.0.0.0 00000000.00000000.00000000.00000000 /0