| CIDR Prefix | Netmask | Binary | Number of Networks |
|---|---|---|---|
| /1 | 128.0.0.0 | 10000000000000000000000000000000 | 128 Class A domains |
| /2 | 192.0.0.0 | 11000000000000000000000000000000 | 64 Class A domains |
| /3 | 224.0.0.0 | 11100000000000000000000000000000 | 32 Class A domains |
| /4 | 240.0.0.0 | 11110000000000000000000000000000 | 16 Class A domains |
| /5 | 248.0.0.0 | 11111000000000000000000000000000 | 8 Class A domains |
| /6 | 252.0.0.0 | 11111100000000000000000000000000 | 4 Class A domains |
| /7 | 254.0.0.0 | 11111110000000000000000000000000 | 2 Class A domains |
| /8 | 255.0.0.0 | 11111111000000000000000000000000 | 1 Class A domain |
| /9 | 255.128.0.0 | 11111111100000000000000000000000 | 128 Class B domains |
| /10 | 255.192.0.0 | 11111111110000000000000000000000 | 64 Class B domains |
| /11 | 255.224.0.0 | 11111111111000000000000000000000 | 32 Class B domains |
| /12 | 255.240.0.0 | 11111111111100000000000000000000 | 16 Class B domains |
| /13 | 255.248.0.0 | 11111111111110000000000000000000 | 8 Class B domains |
| /14 | 255.252.0.0 | 11111111111111000000000000000000 | 4 Class B domains |
| /15 | 255.254.0.0 | 11111111111111100000000000000000 | 2 Class B domains |
| /16 | 255.255.0.0 | 11111111111111110000000000000000 | 1 Class B domain |
| /17 | 255.255.128.0 | 11111111111111111000000000000000 | 128 Class C domains |
| /18 | 255.255.192.0 | 11111111111111111100000000000000 | 64 Class C domains |
| /19 | 255.255.224.0 | 11111111111111111110000000000000 | 32 Class C domains |
| /20 | 255.255.240.0 | 11111111111111111111000000000000 | 16 Class C domains |
| /21 | 255.255.248.0 | 11111111111111111111100000000000 | 8 Class C domains |
| /22 | 255.255.252.0 | 11111111111111111111110000000000 | 4 Class C domains |
| /23 | 255.255.254.0 | 11111111111111111111111000000000 | 2 Class C domains |
| /24 | 255.255.255.0 | 11111111111111111111111100000000 | 1 Class C domain |
| /25 | 255.255.255.128 | 11111111111111111111111110000000 | 128 hosts |
| /26 | 255.255.255.192 | 11111111111111111111111111000000 | 64 hosts |
| /27 | 255.255.255.224 | 11111111111111111111111111100000 | 32 hosts |
| /28 | 255.255.255.240 | 11111111111111111111111111110000 | 16 hosts |
| /29 | 255.255.255.248 | 11111111111111111111111111111000 | 8 hosts |
| /30 | 255.255.255.252 | 11111111111111111111111111111100 | 4 hosts |
| /31 | 255.255.255.254 | 11111111111111111111111111111110 | 2 hosts |
| /32 | 255.255.255.255 | 11111111111111111111111111111111 | 1 host |