Download Calculator. IP subnetting made easy. Whatmask - IP subnet/CIDR Calculator. Online IP CIDR Calculator. CIDR Calculator The CIDR Calculator enables CIDR network calculations using IP address, subnet mask, mask bits, maximum required IP addresses and maximum required subnets. Results of the CIDR calculation provide the wildcard mask, for use with ACL (Access Control Lists), CIDR network address (CIDR route), network address in CIDR notation and the CIDR address range for the resulting CIDR network.
For classful subnets, use the IP Subnet Calculator. For a smart-phone optimized CIDR / VLSM Calculator, visit IP Calc. For ACL (Access Control List) wildcard mask calculations, use the ACL Wildcard Mask Calculator. CIDR - Classless Inter Domain Routing - was adopted to help ease the load imposed on internet and large network backbone routers by the increasing size of routing tables. Large routing tables have several adverse effects: Routers require more memory in order to store and manipulate their routing tables which increases operation costs. A solution to these problems was found in CIDR.