CIDR IP Ranges Calculator

The most interesting aspect of TCP / IP is the subnet mask. Subnet masks point out to IP which bits of the 32-bit IP address refer to the network. It is a parameter included with every IP address that highlights the network portion.
The CIDR abbreviation stands for Classless Inter-Domain Routing and is very similar to a subnet mask. For example, a subnet mask of tells IP that 24 bits determine the network portion of the address, so CIDR simply uses the notation of /24.

In other examples, instead of, CIDR uses a /16 notation, and a subnet mask of is replaced with /28.

Calculate CIDR block, subnet mask for IP range

Within our CIDR calculator, which also calculates the subnet mask, you can get a CIDR as well as a subnet mask preview for the entered IP address ranges. Of course, the second field must have a larger range than the first. Here are a few examples sorted by classes:

  • class A for very large networks -
  • class B for medium network -
  • class C for small network -
  • class D for multicast -
  • class E for experimental purpouses -
To summarize once more. The Cidr calculator gives you the final CIDR and overview of the subnet mask based on the entered IP address ranges. Unlike this useful IPv4 tool, you can use another one Subnet calculator that gives you an overview of the results based on the entered CIDR address, ie the entered IP and netmask.