Calculate your GPA. Your GPA is calculated by your grade point value: * Disclaimer: The GPA Calculator is a tool to help with your grade planning ONLY. To use the GPA calculator, total the number of hours you received for each letter grade. For example, if you had two 3 semester hour courses of A, you would University of Pittsburgh at Johnstown GPA Calculator application. Calculate cumulative GPA and semester GPA needed to meet your personal goal. accurate as the information you provide and is merely a tool meant for your personal use.