Netmask Address Prefix Length Hosts / Class C's / Class B's / Class A's
255.255.255.255 /32 1
255.255.255.254 /31 2
255.255.255.252 /30 4
255.255.255.248 /29 8
255.255.255.240 /28 16
255.255.255.224 /27 32
255.255.255.192 /26 64
255.255.255.128 /25 128
255.255.255.0 /24 (Class C) 256 / 1
255.255.254.0 /23 512 / 2
255.255.252.0 /22 1,024 / 4
255.255.248.0 /21 2,048 / 8
255.255.240.0 /20 4,096 / 16
255.255.224.0 /19 8,192 / 32
255.255.192.0 /18 16,384 / 64
255.255.128.0 /17 32,768 / 128
255.255.0.0 /16 (Class B) 65,536 / 256 / 1
255.254.0.0 /15 131,072 / 512 / 2
255.252.0.0 /14 262,144 / 1024 / 4
255.248.0.0 /13 524,288 / 2048 / 8
255.240.0.0 /12 1,048,576 / 4096 / 16
255.224.0.0 /11 2,097,152 / 8129 / 32
255.192.0.0 /10 4,194,304 / 16,384 / 64
255.128.0.0 /9 8,388,608 / 32,768 / 128
255.0.0.0 /8 (Class A) 16,777,216 / 65,536 / 256 / 1
254.0.0.0 /7 33,554,432 / 131,072 / 512 / 2
252.0.0.0 /6 67,108,864 / 262,144 / 1,024 / 4
248.0.0.0 /5 134,217,728 / 524,288 / 2,048 / 8
240.0.0.0 /4 268,435,456 / 1,048,576 / 4,096 / 16
224.0.0.0 /3 536,870,912 / 2,097,152 / 8,192 / 32
192.0.0.0 /2 1,073,741,824 / 4,194,304 / 16,384 / 64
128.0.0.0 /1 2,147,483,648 / 8,388,608 / 32,768 / 128
0.0.0.0 /0 (The Internet) 4,294,967,296 / 16,777,216 / 65,536 / 256
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