Subnetting Calculator Download
Subnetting Calculator.NET was designed with network administrators in mind. Just enter in the the IP address or Network address and the select the Subnetmask. You will then know what network the address is on, all other networks available, if the Address is a Network ID, Broadcast ID or good for a host, the binary format of the Network ID, Subnet mask and IP Address.
Includes Auto-Update, so you can always get the latest updates (Free).