IPv4 Subnet Cheat Sheet
Last updated
Last updated
r
CIDR
Subnet Mask
Total IPs
Usable IPs
/32
255.255.255.255
1
1
/31
255.255.255.254
2
2*
/30
255.255.255.252
4
2
/29
255.255.255.248
8
6
/28
255.255.255.240
16
14
/27
255.255.255.224
32
30
/26
255.255.255.192
64
62
/25
255.255.255.128
128
126
/24
255.255.255.0
256
254
/23
255.255.254.0
512
510
/22
255.255.252.0
1024
1022
/21
255.255.248.0
2048
2046
/20
255.255.240.0
4096
4094
/19
255.255.224.0
8192
8190
/18
255.255.192.0
16,384
16,382
/17
255.255.128.0
32,768
32,766
/16
255.255.0.0
65,536
65,534
/15
255.254.0.0
131,072
131,070
/14
255.252.0.0
262,144
262,142
/13
255.248.0.0
524,288
524,286
/12
255.240.0.0
1,048,576
1,048,574
/11
255.224.0.0
2,097,152
2,097,150
/10
255.192.0.0
4,194,304
4,194,302
/9
255.128.0.0
8,388,608
8,388,606
/8
255.0.0.0
16,777,216
16,777,214
/7
254.0.0.0
33,554,432
33,554,430
/6
252.0.0.0
67,108,864
67,108,862
/5
248.0.0.0
134,217,728
134,217,726
/4
240.0.0.0
268,435,456
268,435,454
/3
224.0.0.0
536,870,912
536,870,910
/2
192.0.0.0
1,073,741,824
1,073,741,822
/1
128.0.0.0
2,147,483,648
2,147,483,646
Class A
10.0.0.0/8
255.0.0.0
10.0.0.0 – 10.255.255.255
Class B
172.16.0.0/12
255.240.0.0
172.16.0.0 – 172.31.255.255
Class C
192.168.0.0/16
255.255.0.0
192.168.0.0 – 192.168.255.255
Prefix
/48s
/56s
/64s
/24
16M
4G
1T
/25
8M
2G
512G
/26
4M
1G
256G
/27
2M
512M
128G
/28
1M
256M
64G
/29
512K
128M
32G
/30
256K
64M
16G
/31
128K
32M
8G
/32
64K
16M
4G
/33
32K
8M
2G
/34
16K
4M
1G
/35
8K
2M
512M
/36
4K
1M
256M
/37
2K
512K
128M
/38
1K
256K
64M
/39
512
128K
32M
/40
256
64K
16M
/41
128
32K
8M
/42
64
16K
4M
/43
32
8K
2M
/44
16
4K
1M
/45
8
2K
512K
/46
4
1K
256K
/47
2
512
128K
/48
1
256
64K
/49
128
32K
/50
64
16K
/51
32
8K
/52
16
4K
/53
8
2K
/54
4
1K
/55
2
512
/56
1
256
/57
128
/58
64
/59
32
/60
16
/61
8
/62
4
/63
2
/64
1
Bit Value
128
64
32
16
8
4
2
1
*See
Learning
