| RFC1918 name | IP address range | number of addresses | classful description | largest CIDR block (subnet mask) | host id size | mask bits |
| 24-bit block | 10.0.0.0-10.255.255.255 | 16777216 | single class A network | 10.0.0.0/8 (255.0.0.0) | 24 bits | 8 bits |
| 20-bit block | 172.16.0.0-172.31.255.255 | 1048576 | 16 contigous class B networks | 172.16.0.0/12 (255.240.0.0) | 20 bits | 12 bits |
| 16-bit block | 192.168.0.0-192.168.255.255 | 65536 | 256 contigous class C networks | 192.168.0.0/16 (255.255.0.0) | 16 bits | 16 bits |
| APIPA | 169.254.0.0-169.254.255.255 | Automatic Private IP Addressing is a feature on Microsoft operating systems to automatically assign itself an IP address within this range if a Dynamic Host Configuration Protocol server is not available. |
| Localhost | 127.0.0.1-127.255.255.255 | Network testing addresses (also referred to as loop-back addresses) |