Free tool · Reference
Subnet Cheat Sheet
The /0–/32 reference: mask, wildcard, hosts and block size.
| CIDR | Subnet mask | Wildcard | Usable hosts | Total |
|---|---|---|---|---|
| /0 | 0.0.0.0 | 255.255.255.255 | 4,294,967,294 | 4,294,967,296 |
| /1 | 128.0.0.0 | 127.255.255.255 | 2,147,483,646 | 2,147,483,648 |
| /2 | 192.0.0.0 | 63.255.255.255 | 1,073,741,822 | 1,073,741,824 |
| /3 | 224.0.0.0 | 31.255.255.255 | 536,870,910 | 536,870,912 |
| /4 | 240.0.0.0 | 15.255.255.255 | 268,435,454 | 268,435,456 |
| /5 | 248.0.0.0 | 7.255.255.255 | 134,217,726 | 134,217,728 |
| /6 | 252.0.0.0 | 3.255.255.255 | 67,108,862 | 67,108,864 |
| /7 | 254.0.0.0 | 1.255.255.255 | 33,554,430 | 33,554,432 |
| /8 | 255.0.0.0 | 0.255.255.255 | 16,777,214 | 16,777,216 |
| /9 | 255.128.0.0 | 0.127.255.255 | 8,388,606 | 8,388,608 |
| /10 | 255.192.0.0 | 0.63.255.255 | 4,194,302 | 4,194,304 |
| /11 | 255.224.0.0 | 0.31.255.255 | 2,097,150 | 2,097,152 |
| /12 | 255.240.0.0 | 0.15.255.255 | 1,048,574 | 1,048,576 |
| /13 | 255.248.0.0 | 0.7.255.255 | 524,286 | 524,288 |
| /14 | 255.252.0.0 | 0.3.255.255 | 262,142 | 262,144 |
| /15 | 255.254.0.0 | 0.1.255.255 | 131,070 | 131,072 |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,534 | 65,536 |
| /17 | 255.255.128.0 | 0.0.127.255 | 32,766 | 32,768 |
| /18 | 255.255.192.0 | 0.0.63.255 | 16,382 | 16,384 |
| /19 | 255.255.224.0 | 0.0.31.255 | 8,190 | 8,192 |
| /20 | 255.255.240.0 | 0.0.15.255 | 4,094 | 4,096 |
| /21 | 255.255.248.0 | 0.0.7.255 | 2,046 | 2,048 |
| /22 | 255.255.252.0 | 0.0.3.255 | 1,022 | 1,024 |
| /23 | 255.255.254.0 | 0.0.1.255 | 510 | 512 |
| /24 | 255.255.255.0 | 0.0.0.255 | 254 | 256 |
| /25 | 255.255.255.128 | 0.0.0.127 | 126 | 128 |
| /26 | 255.255.255.192 | 0.0.0.63 | 62 | 64 |
| /27 | 255.255.255.224 | 0.0.0.31 | 30 | 32 |
| /28 | 255.255.255.240 | 0.0.0.15 | 14 | 16 |
| /29 | 255.255.255.248 | 0.0.0.7 | 6 | 8 |
| /30 | 255.255.255.252 | 0.0.0.3 | 2 | 4 |
| /31 | 255.255.255.254 | 0.0.0.1 | 2 | 2 |
| /32 | 255.255.255.255 | 0.0.0.0 | 1 | 1 |
About this tool
Free IPv4 subnet cheat sheet. A complete /0 to /32 reference table of CIDR prefix, subnet mask, wildcard mask, usable hosts, total addresses and block size — printable and searchable. Everything runs entirely in your browser — nothing you type is sent to a server.
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