Math · 5 min read
How to Calculate GPA
Credit-weighted letter grades — quality points over credits
Grade point average (GPA) is a credit-weighted mean of course grades on a points scale. This tutorial walks through the usual 4.0 unweighted conversion, a three-course worked example, and a playground that multiplies each letter by its credits. Schools differ on plus/minus values and on whether an A+ is 4.0 or 4.3 — match the scale your transcript uses.
Written by the My Calculator Stack editorial team. About our methods
Weighting schemes and letter-to-point maps differ by school. This page uses a common unweighted 4.0 scale for teaching. It is not an official transcript.
1.What GPA is
GPA is the credit-weighted average of the grade points you earned. A four-credit B pulls the average more than a one-credit A, because each course contributes quality points equal to (grade points × credits). The GPA is then total quality points divided by total credits attempted. Pass/fail, withdrawals, and repeats are school-specific and are left out of this teaching sketch.
2.The formula
Convert each letter to points on the scale your school publishes. A common unweighted 4.0 map is A = 4.0, A− = 3.7, B+ = 3.3, B = 3.0, and so on down to F = 0. Then GPA = Σ(pointsᵢ × creditsᵢ) / Σ creditsᵢ. Credits in the denominator must be positive; a term with no attempted credits is undefined.
\[ \mathrm{GPA} = \frac{\sum (p_i c_i)}{\sum c_i} \]
3.Worked example
Take three courses: an A in a 3-credit class (4.0 × 3 = 12 quality points), a B in a 3-credit class (3.0 × 3 = 9), and a B in a 4-credit class (3.0 × 4 = 12). Quality points total 12 + 9 + 12 = 33. Credits total 3 + 3 + 4 = 10. GPA = 33 / 10 = 3.3. That is the same structure as a weighted grade — scores × weights — which is what the Grade Calculator on this site computes.
\[ \mathrm{GPA}=33/10=3.3 \]
4.Letter × credits playground
Pick a letter and credit load for a few courses. Quality points update as letter × credits; the GPA is their sum over total credits, and the marker travels on a 0–4 scale. This is a teaching widget — no transcript import, no full calculator chrome. Open the Grade Calculator when you want a weighted-average tool with typed scores.
Inline playground
4.0 × 3 = 12
GPA
3.3
33 / 10 = 3.3
Teaching aid only — plus/minus maps differ by school. Set a course’s credits to 0 to skip it.
Open the full Grade calculator →5.Open the full calculator
The Grade Calculator uses the same weighted-average idea (score × weight over total weight) with How it works and FAQ on one page. Browse other math calculators if you need fractions, equations, or a different average next.
Try it yourself
Open the related calculator and put these formulas to work.