Convert grades to grade points
A common U.S. unweighted system maps A to 4.0, B to 3.0, C to 2.0, D to 1.0 and F to 0.0. Many schools add plus/minus values such as 3.7 for A− and 3.3 for B+. Other institutions use different tables, so the official school scale is the correct source.
Weight by credits
GPA is usually credit-weighted. A four-credit course affects the average more than a one-credit course. Multiply each course’s grade points by its credits to calculate quality points.
The formula
Add all quality points and divide by the total GPA-bearing credits. The structure is GPA = Σ(grade points × credits) ÷ Σ(credits). Courses marked pass/fail, withdrawals or repeats may be treated differently by the institution.
Worked example
A in a 3-credit course contributes 12 quality points. B in a 4-credit course contributes 12. B+ at 3.3 in a 3-credit course contributes 9.9. Total quality points are 33.9 over 10 credits, so the estimated GPA is 3.39.
Why the transcript can differ
Schools may exclude repeated courses, recalculate transfer credit, use separate major GPAs or apply academic forgiveness policies. A calculator estimates the arithmetic; only the institution determines the official GPA.
Semester GPA vs cumulative GPA
A semester GPA uses only courses in that term. A cumulative GPA combines eligible coursework across terms. Because cumulative GPA includes many more credits, one new course usually changes it less than it changes the semester GPA. Always confirm which GPA you are trying to estimate.
Related resources
Reviewed: October 2026. CurioLift explanations are educational; when a school, instructor or required style guide uses different rules, those rules take priority.