A subnet is a logically visible subdivision of an IP network. The practice of dividing a network into subnetworks is called subnetting. More informations on Wikipedia
This tool will help you to compute information about IP subnetting. It's easy to use. In the following form you can enter differents addresses formats:
|IP & CIDR Netmask||10.0.0.1/22|
|IP & Netmask||10.0.0.1 255.255.252.0|
|IP & Wildcard Mask||10.0.0.1 0.0.3.255|
The behavior of this application is the same that the ipcalc binary of GNU/Linux system's !