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CIDR Calculator

Fill in the IP address in CIDR notation and the calculator will display the network address, usable IPs, broadcast address, and network mask.
See also my IP calculator using an IP range.
• All IP address parts must contain an integer not greater than 255.
• The CIDR netmask must be an integer greater than 0 and not greater than 30. 1The calculator displays the resulting IP addresses to correspond to the CIDR mask.

Fill in the IP address and CIDR mask
1234CIDR netmask
/   

   

Type in IP and CIDR mask all in one field
e.g. 192.168.0.0/24   

   

The smallest possible subnet is 4 IPs: a network number, 2 usable IPs, and a broadcast address. 1Thus the CIDR mask may not be greater than 30.

Private IPv4 addresses as per RFC 1918

10.0.0.0/8
172.16.0.0/12
192.168.0.0/16

Automatic Private IP addresses reserved by IANA.

169.254.0.0/16

DISCLAIMER:This online CIDR calculator comes with no warranty at all. It is provided as is. Use at your discretion and risks. I am not responsible for its misuse, damages, or losses that can be caused directly or indirectly.

Stuff is written here for the uninitiated and no prior knowledge on the subject is presumed.

For support, use the Brazil Firewall forums so everyone can share the information. I monitor the English forum as bobbb.

Updated 2009/01/02

© copyrightcopyright for the writing. The ideas and code are free. Robert Bonomo
bobbb at myrealbox dot com W3C logo
Comments? or an error? Write me.