This application will help you to perform subnetting using Variable Length Subnet Mask (VLSM).

With this application you can get:
Number of IP network.
Number of Host network.
Network ID
Braodcast network.
Network prefix.

You just need to place the network address and the number of hosts per network and application will do the rest.

You can share the results with friends and colleagues using the option that let the application share the results.

Enjoy it!!!.