May 162011
 

 

CIDR  Netmask # Networks # Hosts
  /1 128.0.0.0 128 A 2,147,483,392
  /2 192.0.0.0 64 A 1,073,741,696
  /3 224.0.0.0 32 A 536,870,848
  /4 240.0.0.0 16 A 268,435,424
  /5 248.0.0.0 8 A 134,217,712
  /6 252.0.0.0 4 A 67,108,856
  /7 254.0.0.0 2 A 33,554,428
  /8 255.0.0.0 1 A   16,777,214  
  /9 255.128.0.0 128 B 8,388,352
  /10 255.192.0.0 64 B 4,194,176
  /11 255.224.0.0 32 B 2,097,088
  /12 255.240.0.0 16 B 1,048,544
  /13 255.248.0.0 8 B 524,272
  /14 255.252.0.0 4 B 262,136
  /15 255.254.0.0 2 B 131,068
  /16 255.255.0.0 1 B   65,024  
  /17 255.255.128.0 128 C 32,512
  /18 255.255.192.0 64 C 16,256
  /19 255.255.224.0 32 C 8,128
  /20 255.255.240.0 16 C 4,064
  /21 255.255.248.0 8 C 2,032
  /22 255.255.252.0 4 C 1,016
  /23 255.255.254.0 2 C 508
  /24 255.255.255.0 1 C   254  
  /25 255.255.255.128 2 subnets 124
  /26 255.255.255.192 4 subnets 62
  /27 255.255.255.224 8 subnets 30
  /28 255.255.255.240 16 subnets 14
  /29 255.255.255.248 32 subnets 6
  /30 255.255.255.252 64 subnets 2
  /31 255.255.255.254 none none
  /32 255.255.255.255 1/256 C 1 (broadcast)