This tool will help you to find out your network class and calculate Network Mask, Subnet Mask and Maximum subnets.
To open the IP Subnet Mask Calculator you just need to open the Template Gallery and make a double click on the corresponding icon in the Computers and Network section.
To receive a results you need to enter the TCP/IP Network Address which is your host address and desired subnets number in the corresponding fields of the calculator.
Note: To enter the data in the field you need to select the field by making the left mouse click on it.
When you have all data entered just make a double click on the "Calculate" button. You will see the calculated data in the corresponding fields of the calculator.