Subnet Mask Cheat Sheet
| Prefix Length | Number of Addresses | Number of Hosts | Netmask | Wildcard Mask | More Detail |
|---|---|---|---|---|---|
| /32 | 1 | 1* | 255.255.255.255 | 0.0.0.0 | Link to /32 Details |
| /31 | 2 | 2* | 255.255.255.254 | 0.0.0.1 | Link to /31 Details |
| /30 | 4 | 2 | 255.255.255.252 | 0.0.0.3 | Link to /30 Details |
| /29 | 8 | 6 | 255.255.255.248 | 0.0.0.7 | Link to /29 Details |
| /28 | 16 | 14 | 255.255.255.240 | 0.0.0.15 | Link to /28 Details |
| /27 | 32 | 30 | 255.255.255.224 | 0.0.0.31 | Link to /27 Details |
| /26 | 64 | 62 | 255.255.255.192 | 0.0.0.63 | Link to /26 Details |
| /25 | 128 | 126 | 255.255.255.128 | 0.0.0.127 | Link to /25 Details |
| /24 | 256 | 254 | 255.255.255.0 | 0.0.0.255 | Link to /24 Details |
| /23 | 512 | 510 | 255.255.254.0 | 0.0.1.255 | Link to /23 Details |
| /22 | 1024 | 1022 | 255.255.252.0 | 0.0.3.255 | Link to /22 Details |
| /21 | 2048 | 2046 | 255.255.248.0 | 0.0.7.255 | Link to /21 Details |
| /20 | 4096 | 4094 | 255.255.240.0 | 0.0.15.255 | Link to /20 Details |
| /19 | 8192 | 8190 | 255.255.224.0 | 0.0.31.255 | Link to /19 Details |
| /18 | 16384 | 16382 | 255.255.192.0 | 0.0.63.255 | Link to /18 Details |
| /17 | 32768 | 32766 | 255.255.128.0 | 0.0.127.255 | Link to /17 Details |
| /16 | 65536 | 65534 | 255.255.0.0 | 0.0.255.255 | Link to /16 Details |
Subnet Mask Cheat Sheet For Class C network
Note: In the number of subnets column, the value outside “()” denotes the total number of subnets, while the value inside “()” denotes the number of usable subnets after two subnets have been subtracted according to RFC guidelines.
| Prefix Length | Netmask | Number of Subnets (Number of Usable Subnets) | Number of Hosts | More Details |
|---|---|---|---|---|
| /24 | 255.255.255.0 | 0 | 254 | Link to /24 Details |
| /25 | 255.255.255.128 | 2(0) | 126 | Link to /25 Details |
| /26 | 255.255.255.192 | 4(2) | 62 | Link to /26 Details |
| /27 | 255.255.255.224 | 8(6) | 30 | Link to /27 Details |
| /28 | 255.255.255.240 | 16(14) | 14 | Link to /28 Details |
| /29 | 255.255.255.248 | 32(30) | 6 | Link to /29 Details |
| /30 | 255.255.255.252 | 64(62) | 2 | Link to /30 Details |
| /31 | 255.255.255.254 | 128(126) | 0 | Link to /31 Details |
| /32 | 255.255.255.255 | N/A | N/A | Link to /32 Details |
Subnet Mask Cheat Sheet For Class B network
| Prefix Length | Netmask | Number of Subnets (Number of Usable subnets) | Number of Hosts | More Details |
|---|---|---|---|---|
| /30 | 255.255.255.252 | 16384 (16382) | 2 | Link to /30 Details |
| /29 | 255.255.255.248 | 8192 (8190) | 6 | Link to /29 Details |
| /28 | 255.255.255.240 | 4096 (4094) | 14 | Link to /28 Details |
| /27 | 255.255.255.224 | 2048 (2046) | 30 | Link to /27 Details |
| /26 | 255.255.255.192 | 1024 (1022) | 62 | Link to /26 Details |
| /25 | 255.255.255.128 | 512 (510) | 126 | Link to /25 Details |
| /24 | 255.255.255.0 | 256 (254) | 254 | Link to /24 Details |
| /23 | 255.255.254.0 | 128 (126) | 510 | Link to /23 Details |
| /22 | 255.255.252.0 | 64 (62) | 1,022 | Link to /22 Details |
| /21 | 255.255.248.0 | 32 (30) | 2,046 | Link to /21 Details |
| /20 | 255.255.240.0 | 16 (14) | 4,094 | Link to /20 Details |
| /19 | 255.255.224.0 | 8 (6) | 8,190 | Link to /19 Details |
| /18 | 255.255.192.0 | 4 (2) | 16,382 | Link to /18 Details |
| /17 | 255.255.128.0 | 2 (0) | 32,766 | Link to /17 Details |
| /16 | 255.255.0.0 | 0 | 65,534 | Link to /16 Details |
Subnet Mask Cheat Sheet For Class A network
| Prefix length | Netmask | Number of Subnets(Number of usable subnets) | Number of Hosts |
|---|---|---|---|
| /8 | 255.0.0.0 | 0 | 16777214 |
| /9 | 255.128.0.0 | 2 (0) | 8388606 |
| /10 | 255.192.0.0 | 4 (2) | 4194302 |
| /11 | 255.224.0.0 | 8 (6) | 2097150 |
| /12 | 255.240.0.0 | 16 (14) | 1048574 |
| /13 | 255.248.0.0 | 32 (30) | 524286 |
| /14 | 255.252.0.0 | 64 (62) | 262142 |
| /15 | 255.254.0.0 | 128 (126) | 131070 |
| /16 | 255.255.0.0 | 256 (254) | 65534 |
| /17 | 255.255.128.0 | 512 (510) | 32766 |
| /18 | 255.255.192.0 | 1024 (1022) | 16382 |
| /19 | 255.255.224.0 | 2048 (2046) | 8190 |
| /20 | 255.255.240.0 | 4096 (4094) | 4094 |
| /21 | 255.255.248.0 | 8192 (8190) | 2046 |
| /22 | 255.255.252.0 | 16384 (16382) | 1022 |
| /23 | 255.255.254.0 | 32768 (32766) | 510 |
| /24 | 255.255.255.0 | 65536 (65534) | 254 |
| /25 | 255.255.255.128 | 131072 (131070) | 126 |
| /26 | 255.255.255.192 | 262144 (262142) | 62 |
| /27 | 255.255.255.224 | 524288 (524286) | 30 |
| /28 | 255.255.255.240 | 1048576 (1048574) | 14 |
| /29 | 255.255.255.248 | 2097152 (2097150) | 6 |
| /30 | 255.255.255.252 | 4194304 (4194302) | 2 |
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