IP Subnet Chart

Class C Address Space
Prefix Subnet Host Usable
/32 255.255.255.255 1 1
/31 255.255.255.254 2 0
/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

Class B Space is denoted in numbers of Class C's
Ripe Subnet # of Class C's
/23 255.255.254.0 2
/22 255.255.252.0 4
/21 255.255.248.0 8
/20 255.255.240.0 16
/19 255.255.224.0 32
/18 255.255.192.0 64
/17 255.255.128.0 128
/16 255.255.0.0 256

Private IP Addresses

RFC 1918 requests that organizations make use of the private Internet address space for hosts that require IP connectivity within their enterprise network, but do not require external connections to the global Internet. For this purpose, the IANA has reserved the following three address blocks for private internets:

  • 10.0.0.0/8
  • 127.0.0.0/8
  • 172.16.0.0/12
  • 192.168.0.0/16

IP's above 224.0.0.0 are used for both multicast and experimental purposes.