Day to day administrators find themselves having to work with subnets within networks when, for example, troubleshooting routing problems or planning IP address allocation and provisioning. Manually determining which subnets are valid within a particular network can be time consuming.
IPv4 Subnet Calculator can generate these lists to save administrators precious time. Administrators can select a network and subnet length and generate a list of valid subnets. Selected subnets from the list can be copied to the Windows clipboard making them available to other applications.

The license of this software is Freeware, you can free download and free use this ip utility software.