CIDR Address Blocks and “Classful” Address Equivalents
|
# of Bits For Network ID |
# of Bits For Host ID |
# of Hosts Per Network |
Prefix Length in Slash Notation |
Equivalent Subnet Mask |
# of Equivalent “Classful” Addressing Networks |
||
|
Class A |
Class B |
Class C |
|||||
|
1 |
31 |
2,147,483,646 |
/1 |
128.0.0.0 |
128 |
— |
— |
|
2 |
30 |
1,073,741,822 |
/2 |
192.0.0.0 |
64 |
— |
— |
|
3 |
29 |
536,870,910 |
/3 |
224.0.0.0 |
32 |
— |
— |
|
4 |
28 |
268,435,454 |
/4 |
240.0.0.0 |
16 |
— |
— |
|
5 |
27 |
134,217,726 |
/5 |
248.0.0.0 |
8 |
— |
— |
|
6 |
26 |
67,108,862 |
/6 |
252.0.0.0 |
4 |
— |
— |
|
7 |
25 |
33,554,430 |
/7 |
254.0.0.0 |
2 |
— |
— |
|
8 |
24 |
16,777,214 |
/8 |
255.0.0.0 |
1 |
256 |
— |
|
9 |
23 |
8,388,606 |
/9 |
255.128.0.0 |
1/2 |
128 |
— |
|
10 |
22 |
4,194,302 |
/10 |
255.192.0.0 |
1/4 |
64 |
— |
|
11 |
21 |
2,097,150 |
/11 |
255.224.0.0 |
1/8 |
32 |
— |
|
12 |
20 |
1,048,574 |
/12 |
255.240.0.0 |
1/16 |
16 |
— |
|
13 |
19 |
524,286 |
/13 |
255.248.0.0 |
1/32 |
8 |
— |
|
14 |
18 |
262,142 |
/14 |
255.252.0.0 |
1/64 |
4 |
— |
|
15 |
17 |
131,070 |
/15 |
255.254.0.0 |
1/128 |
2 |
— |
|
16 |
16 |
65,534 |
/16 |
255.255.0.0 |
1/256 |
1 |
256 |
|
17 |
15 |
32,766 |
/17 |
255.255.128.0 |
— |
1/2 |
128 |
|
18 |
14 |
16,382 |
/18 |
255.255.192.0 |
— |
1/4 |
64 |
|
19 |
13 |
8,190 |
/19 |
255.255.224.0 |
— |
1/8 |
32 |
|
20 |
12 |
4,094 |
/20 |
255.255.240.0 |
— |
1/16 |
16 |
|
21 |
11 |
2,046 |
/21 |
255.255.248.0 |
— |
1/32 |
8 |
|
22 |
10 |
1,022 |
/22 |
255.255.252.0 |
— |
1/64 |
4 |
|
23 |
9 |
510 |
/23 |
255.255.254.0 |
— |
1/128 |
2 |
|
24 |
8 |
254 |
/24 |
255.255.255.0 |
— |
1/256 |
1 |
|
25 |
7 |
126 |
/25 |
255.255.255.128 |
— |
— |
1/2 |
|
26 |
6 |
62 |
/26 |
255.255.255.192 |
— |
— |
1/4 |
|
27 |
5 |
30 |
/27 |
255.255.255.224 |
— |
— |
1/8 |
|
28 |
4 |
14 |
/28 |
255.255.255.240 |
— |
— |
1/16 |
|
29 |
3 |
6 |
/29 |
255.255.255.248 |
— |
— |
1/32 |
|
30 |
2 |
2 |
/30 |
255.255.255.252 |
— |
— |
1/64 |