| Netmask | ||||
| # bits | Nbre d'adresses | Usable hosts |
netmask | |
| /4 | 268435456 | 268435454 | 240.0.0.0 | |
| /5 | 134217728 | 134217726 | 248.0.0.0 | |
| /6 | 67108864 | 67108862 | 252.0.0.0 | |
| /7 | 33554432 | 33554430 | 254.0.0.0 | |
| /8 | 16777216 | 16777214 | 255.0.0.0 | class A network |
| /9 | 8388608 | 8388606 | 255.128.0.0 | |
| /10 | 4194304 | 4194302 | 255.192.0.0 | |
| /11 | 2097152 | 2097150 | 255.224.0.0 | |
| /12 | 1048576 | 1048574 | 255.240.0.0 | |
| /13 | 524288 | 524286 | 255.248.0.0 | |
| /14 | 262144 | 262142 | 255.252.0.0 | |
| /15 | 131072 | 131070 | 255.254.0.0 | |
| /16 | 65536 | 65534 | 255.255.0.0 | class B network |
| /17 | 32768 | 32766 | 255.255.128.0 | |
| /18 | 16384 | 16382 | 255.255.192.0 | |
| /19 | 8192 | 8190 | 255.255.224.0 | |
| /20 | 4096 | 4094 | 255.255.240.0 | |
| /21 | 2048 | 2046 | 255.255.248.0 | |
| /22 | 1024 | 1022 | 255.255.252.0 | |
| /23 | 512 | 510 | 255.255.254.0 | |
| /24 | 256 | 254 | 255.255.255.0 | class C network |
| /25 | 128 | 126 | 255.255.255.128 | |
| /26 | 64 | 62 | 255.255.255.192 | |
| /27 | 32 | 30 | 255.255.255.224 | |
| /28 | 16 | 14 | 255.255.255.240 | |
| /29 | 8 | 6 | 255.255.255.248 | |
| /30 | 4 | 2 | 255.255.255.252 | |
