How GPA is calculated
GPA is a credit-weighted average, not a simple mean of your grades. Each letter grade maps to grade points on the 4.0 scale — A is 4.0, A- is 3.7, B+ is 3.3, B is 3.0, and so on down to F at 0.0. You multiply each course's grade points by its credit hours to get quality points, add up all the quality points, and divide by the total credit hours. That weighting means a high grade in a four-credit class moves your GPA more than the same grade in a one-credit class.
Why credit hours matter
Because the average is weighted, credit hours are as important as the grades themselves. A student who earns an A in a heavy four-credit course and a C in a light one-credit course ends up much closer to the A than a plain average would suggest. Entering accurate credit hours — usually shown on your syllabus or transcript — is therefore essential; guessing them is the most common reason a hand-calculated GPA doesn't match the registrar's.
Unweighted versus weighted GPA
This calculator produces an unweighted GPA capped at 4.0, which is the standard for most colleges. Many high schools use a weighted scale that adds points for honors, AP, or IB courses — often making an A worth 5.0 in those classes — so a weighted GPA can exceed 4.0. If your school weights advanced courses, this tool will understate that boost; use it for the unweighted figure, which colleges frequently recalculate anyway for fair comparison.
A worked example
Suppose you take English (A, 3 credits), Calculus (B+, 4 credits), Chemistry (A-, 4 credits), and History (B, 3 credits). The quality points are 12.0, 13.2, 14.8, and 9.0 — totaling 49.0 over 14 credit hours, for a GPA of 3.50. Change the Calculus grade to an A and the total jumps to 51.8, lifting the GPA to about 3.70, which shows how a single heavy course can swing the average.
Tips for using your GPA
Add your in-progress courses with expected grades to project a term GPA, or model "what if" scenarios before finals to see which classes give you the most leverage. To find your cumulative GPA across terms, include every graded course you have taken. Remember that pass/fail courses and withdrawals usually don't carry grade points and should be left out.