Block Size | IP Addresses | Usable Hosts | Netmask |
---|---|---|---|
/30 | 4 | 2 | 255.255.255.252 |
/29 | 8 | 6 | 255.255.255.248 |
/28 | 16 | 14 | 255.255.255.240 |
/27 | 32 | 30 | 255.255.255.224 |
/26 | 64 | 62 | 255.255.255.192 |
/25 | 128 | 126 | 255.255.255.128 |
/24 | 256 | 254 | 255.255.255.0 |
/23 | 512 | 510 | 255.255.254.0 |
/22 | 1024 | 1022 | 255.255.252.0 |
/21 | 2048 | 2046 | 255.255.248.0 |
/20 | 4096 | 4094 | 255.255.240.0 |
/19 | 8192 | 8190 | 255.255.224.0 |
/18 | 16384 | 16382 | 255.255.192.0 |
/17 | 32768 | 32766 | 255.255.128.0 |
/16 | 65536 | 65534 | 255.255.0.0 |
Also check out our subnetting calclulator.