Mask | Hosts | Usable | Netmask | Hex | Mask |
/30 | 4 | 2 | 255.255.255.252 | fffffffc | this is 1/64 of a Class C net |
/29 | 8 | 6 | 255.255.255.248 | fffffff8 | this is 1/32 of a Class C net |
/28 | 16 | 14 | 255.255.255.240 | fffffff0 | this is 1/16 of a Class C net |
/27 | 32 | 30 | 255.255.255.224 | ffffffe0 | this is 1/8 of a Class C net |
/26 | 64 | 62 | 255.255.255.192 | ffffffc0 | this is 1/4 of a Class C net |
/24 | 256 | 254 | 255.255.255.0 | ffffff00 | this is a Class C net |
/23 | 512 | 510 | 255.255.254.0 | fffffe00 | these are 2 Class C net |
/22 | 1024 | 1022 | 255.255.252.0 | fffffc00 | these are 4 Class C net |
/21 | 2048 | 2046 | 255.255.248.0 | fffff800 | these are 8 Class C net |
/20 | 4096 | 4094 | 255.255.240.0 | fffff000 | these are 16 Class C net |
/19 | 8192 | 8190 | 255.255.224.0 | ffffe000 | these are 32 Class C net |
/18 | 16384 | 16382 | 255.255.192.0 | ffffc000 | these are 64 Class C net |
/17 | 32768 | 32766 | 255.255.128.0 | ffff8000 | these are 128 Class C net |
/16 | 65536 | 65534 | 255.255.0.0 | ffff0000 | these are 256 Class C net = Class B net |