The GPA Formula, One Course at a Time

A GPA is not an average of your grades. It's an average of your grades times their credits — which means a 4-credit B+ pulls harder than a 3-credit A, and the whole system reduces to one multiplication per course. Here is the machinery, one course at a time.

From letters to grade points

Every letter grade maps to a number on the 4.0 scale: A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0.0. Plus and minus grades slice between them in 0.3 steps — A− = 3.7, B+ = 3.3, B− = 2.7, down through D− = 0.7. One asymmetry surprises people: an A+ is worth 4.0 here, not 4.3, because most institutions cap the top of the scale (the schools that do award 4.3 compute a different average on purpose). The tool accepts all thirteen grades: A+, A, A−, B+, B, B−, C+, C, C−, D+, D, D−, and F.

Quality points: credits are the weights

Each course contributes quality points — grade points multiplied by credit hours. A B+ in a 4-credit course contributes 3.3 × 4 = 13.2 quality points; an A in a 3-credit course contributes 12. Those raw grade points (3.3 vs 4.0) suggest the A "won," but the B+ course consumed more of your schedule, so it owns more of the average. That is the entire trick: the GPA is a credit-weighted mean, and quality points are the weighted sum before division.

A full semester, worked through

Enter three courses — A 3, B+ 4, A− 3 — and the arithmetic runs like this:

A  × 3 credits = 12.0 points
B+ × 4 credits = 13.2 points
A− × 3 credits = 11.1 points
total: 36.3 points ÷ 10 credits = 3.63 GPA

Notice the B+ course supplied the largest share of quality points despite the lower grade. Swap the credits — make the A the 4-credit course and the B+ the 3-credit one — and the same letter grades produce (16 + 9.9 + 11.1) ÷ 10 = 3.70. Nothing about your performance changed; the weighting did. This is why Registrar's math treats "what did you take" as seriously as "what did you get."

The input grammar and its default

The calculator reads one course per line as grade credits, splitting on spaces or commas. The credits are optional: a line that is just A counts as a 1-credit A. That default is convenient for quick checks but silently skews real transcripts — a seminar listed as "B+" weighs the same as "B+ 1," not as its actual 3 credits. For anything official-looking, type the credits explicitly on every line. The result rounds to two decimals: 36.3 ÷ 10 lands exactly on 3.63, but a 36.25 would report as 3.63 too.

Course GPA vs cumulative GPA

What this tool computes is the building block, not the building. Your transcript's overall number is a weighted average of semesters, where each semester GPA enters weighted by that term's credits — the cumulative GPA explainer covers why that second weighting makes some terms shout and others whisper, and why recovery from a bad year is slower than it feels. The two layers use identical math at different zoom levels: courses → term, terms → transcript. And if your grades arrive as percentages rather than letters, GPA scale conversion explains why 85% is 3.7 at one school and 4.0 at another before you enter anything.

Try it yourself

The GPA Calculator turns a list of grade credits lines into your term GPA, with the per-course quality points shown so you can audit the weighting. To average whole semesters into a transcript number, use the Cumulative GPA Calculator. And if you're asking the forward-looking question — "what do I need on the final to land a B+ in this course?" — that's a different formula entirely, handled by the Final Grade Calculator.