Subnet Mask Cheat Sheet
| Prefix | Useable IP Addresses | Subnet Mask | Bits |
|---|---|---|---|
| /32 | 1 | 255.255.255.255 | 0 |
| /31 | 0 | 255.255.255.254 | 1 |
| /30 | 2 | 255.255.255.252 | 2 |
| /29 | 6 | 255.255.255.248 | 3 |
| /28 | 14 | 255.255.255.240 | 4 |
| /27 | 30 | 255.255.255.224 | 5 |
| /26 | 62 | 255.255.255.192 | 6 |
| /25 | 126 | 255.255.255.128 | 7 |
| /24 | 254 | 255.255.255.0 | 8 |
| /23 | 510 | 255.255.254.0 | 9 |
| /22 | 1,022 | 255.255.252.0 | 10 |
| /21 | 2,046 | 255.255.248.0 | 11 |
| /20 | 4,094 | 255.255.240.0 | 12 |
| /19 | 8,190 | 255.255.224.0 | 13 |
| /18 | 16,382 | 255.255.192.0 | 14 |
| /17 | 32,766 | 255.255.128.0 | 15 |
| /16 | 65,534 | 255.255.0.0 | 16 |
| /15 | 131,070 | 255.254.0.0 | 17 |
| /14 | 262,142 | 255.252.0.0 | 18 |
| /13 | 524,286 | 255.248.0.0 | 19 |
| /12 | 1,048,574 | 255.240.0.0 | 20 |
| /11 | 2,097,150 | 255.224.0.0 | 21 |
| /10 | 4,194,302 | 255.192.0.0 | 22 |
| /9 | 8,388,606 | 255.128.0.0 | 23 |
| /8 | 16,777,214 | 255.0.0.0 | 24 |
| /7 | 33,554,430 | 254.0.0.0 | 25 |
| /6 | 67,108,862 | 252.0.0.0 | 26 |
| /5 | 134,217,726 | 248.0.0.0 | 27 |
| /4 | 268,435,454 | 240.0.0.0 | 28 |
| /3 | 536,870,910 | 224.0.0.0 | 29 |
| /2 | 1,073,741,822 | 192.0.0.0 | 30 |
| /1 | 2,147,483,646 | 128.0.0.0 | 31 |
| /0 | 4,294,967,294 | 0.0.0.0 | 32 |