Internet Protocol (IPv4) Subnet Chart

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