- Class A addresses have their first octet in the range 1 to 126 (binary address begins with 0).
- Class B addresses have their first octet in the range 128 to 191 (binary address begins with 10).
- Class C addresses have their first octet in the range 192 to 223 (binary address begins with 110).
| CIDR |
Subnet Mask |
Number of Subnets |
Number of Hosts per Subnet
|
| Class A Network
|
| /8 |
255.0.0.0 |
1 |
16777214
|
| /9 |
255.128.0.0 |
2 |
8388606
|
| /10 |
255.192.0.0 |
4 |
4194302
|
| /11 |
255.224.0.0 |
8 |
2097150
|
| /12 |
255.240.0.0 |
16 |
1048574
|
| /13 |
255.248.0.0 |
32 |
524286
|
| /14 |
255.252.0.0 |
64 |
262142
|
| /15 |
255.254.0.0 |
128 |
131070
|
| Class B Network
|
| /16 |
255.255.0.0 |
1 |
65534
|
| /17 |
255.255.128.0 |
2 |
32766
|
| /18 |
255.255.192.0 |
4 |
16382
|
| /19 |
255.255.224.0 |
8 |
8190
|
| /20 |
255.255.240.0 |
16 |
4094
|
| /21 |
255.255.248.0 |
32 |
2046
|
| /22 |
255.255.252.0 |
64 |
1022
|
| /23 |
255.255.254.0 |
128 |
510
|
| Class C Network
|
| /24 |
255.255.255.0 |
1 |
254
|
| /25 |
255.255.255.128 |
2 |
126
|
| /26 |
255.255.255.192 |
4 |
62
|
| /27 |
255.255.255.224 |
8 |
30
|
| /28 |
255.255.255.240 |
16 |
14
|
| /29 |
255.255.255.248 |
32 |
6
|
| /30 |
255.255.255.252 |
64 |
2
|
| /32 |
255.255.255.255 |
255 |
1 - Loopback
|
http://www.subnet-calculator.com/subnet.php
