IP Subnet Chart

Prefix Subnet # of IP's Blocks
/24 255.255.255.0 256 1 Class C
/25 255.255.255.128 128 1/2 Class C
/26 255.255.255.192 64 1/4 Class C
/27 255.255.255.224 32 1/8 Class C
/28 255.255.255.240 16 1/16 Class C
/29 255.255.255.248 8 1/32 Class C
/30 255.255.255.252 4 1/64 Class C
/31 255.255.255.254 2 1/128 Class C
/32 255.255.255.255 1 Single IP

RIPE Subnet # of Class C's
/16 255.255.0.0 256
/17 255.255.128.0 128
/18 255.255.192.0 64
/19 255.255.224.0 32
/20 255.255.240.0 16
/21 255.255.248.0 8
/22 255.255.252.0 4
/23 255.255.254.0 2

Private IP Ranges

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