Ths is an Internet Protocol (IPv4) Subnet Chart. You can use this to quickly look up how your might need to subnet your network. At the bottom there is a quick how-to on calculating subnets.
For more information on subnetting, see RFC 1817 and RFC 1812.
Class address ranges:
- Class A = 1.0.0.0 to 126.0.0.0
- Class B = 128.0.0.0 to 191.255.0.0
- Class C = 192.0.1.0 to 223.255.255.0
Reserved address ranges for private (non-routed) use (see RFC 1918):
- 10.0.0.0 -> 10.255.255.255
- 172.16.0.0 -> 172.31.255.255
- 192.168.0.0 -> 192.168.255.255
Other reserved addresses:
- 127.0.0.0 is reserved for loopback and IPC on the local host
- 224.0.0.0 -> 239.255.255.255 is reserved for multicast addresses
Chart notes:
- Number of Subnets – “( )” Refers to the number of effective subnets, since the use of subnet numbers of all 0s or all 1s is highly frowned upon and RFC non-compliant.
- Number of Hosts – Refers to the number of effective hosts, excluding the network and broadcast address.
Class A
| Network Bits | Subnet Mask | Number of 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 |
Class B
| Network Bits | Subnet Mask | Number of Subnets | Number of Hosts |
| /16 | 255.255.0.0 | 0 | 65534 |
| /17 | 255.255.128.0 | 2 (0) | 32766 |
| /18 | 255.255.192.0 | 4 (2) | 16382 |
| /19 | 255.255.224.0 | 8 (6) | 8190 |
| /20 | 255.255.240.0 | 16 (14) | 4094 |
| /21 | 255.255.248.0 | 32 (30) | 2046 |
| /22 | 255.255.252.0 | 64 (62) | 1022 |
| /23 | 255.255.254.0 | 128 (126) | 510 |
| /24 | 255.255.255.0 | 256 (254) | 254 |
| /25 | 255.255.255.128 | 512 (510) | 126 |
| /26 | 255.255.255.192 | 1024 (1022) | 62 |
| /27 | 255.255.255.224 | 2048 (2046) | 30 |
| /28 | 255.255.255.240 | 4096 (4094) | 14 |
| /29 | 255.255.255.248 | 8192 (8190) | 6 |
| /30 | 255.255.255.252 | 16384 (16382) | 2 |
Class C
| Network Bits | Subnet Mask | Number of Subnets | Number of Hosts |
| /24 | 255.255.255.0 | 0 | 254 |
| /25 | 255.255.255.128 | 2 (0) | 126 |
| /26 | 255.255.255.192 | 4 (2) | 62 |
| /27 | 255.255.255.224 | 8 (6) | 30 |
| /28 | 255.255.255.240 | 16 (14) | 14 |
| /29 | 255.255.255.248 | 32 (30) | 6 |
| /30 | 255.255.255.252 | 64 (62) | 2 |
Supernetting (CIDR) Chart
- CIDR – Classless Inter-Domain Routing.
- Note: The Number of Class C networks must be contiguous.
For example, 192.169.1.0/22 represents the following block of addresses:
192.169.1.0, 192.169.2.0, 192.169.3.0 and 192.169.4.0.
Class C
| CIDR Block | Supernet Mask | Number of Class C Addresses | Number of Hosts |
| /14 | 255.252.0.0 | 1024 | 262144 |
| /15 | 255.254.0.0 | 512 | 131072 |
| /16 | 255.255.0.0 | 256 | 65536 |
| /17 | 255.255.128.0 | 128 | 32768 |
| /18 | 255.255.192.0 | 64 | 16384 |
| /19 | 255.255.224.0 | 32 | 8192 |
| /20 | 255.255.240.0 | 16 | 4096 |
| /21 | 255.255.248.0 | 8 | 2048 |
| /22 | 255.255.252.0 | 4 | 1024 |
| /23 | 255.255.254.0 | 2 | 512 |