How to Calculate GPA on a 4.0 Scale

GPA looks mysterious until you see that it is just a weighted average. Once you know the two ingredients — grade points and credits — you can calculate it for any semester, and understand exactly what a tough class does to your average. Here is the whole system.

The 4.0 scale

Each letter grade maps to a number of grade points:

Letter	Points		Letter	Points
A	4.0		C+	2.3
A−	3.7		C	2.0
B+	3.3		C−	1.7
B	3.0		D+	1.3
B−	2.7		D	1.0
			F	0.0

(Many schools award 4.3 for an A+ — check your registrar’s table; the standard version caps at 4.0.)

Step 1: Convert grades to points

Take your semester’s final letter grades and write the point value next to each. A semester with an A, a B+ and a B− becomes 4.0, 3.3 and 2.7.

Step 2: Weight by credits

A 4-credit calculus course counts twice as much as a 2-credit seminar. For each course multiply points × credits (these are “quality points”), add them up, and divide by total credits:

GPA = Σ (grade points × credits) ÷ Σ credits

Worked example:

Course	Grade	Points	Credits	Quality points
Calculus I	A	4.0	4	16.0
English Comp	B+	3.3	3	9.9
Psychology	B−	2.7	3	8.1

GPA = (16.0 + 9.9 + 8.1) ÷ 10 = 3.40

Notice what happened: the 4-credit A pulled harder than the 3-credit B−. This is why one heavy-credit course can move your GPA more than two light ones — and why protecting your grade in high-credit classes matters.

Step 3: Cumulative GPA

Your cumulative average is the same formula across every term:

Cumulative = (previous GPA × previous credits + this term's quality points) ÷ (previous credits + this term's credits)

Example: 3.50 over 30 credits, plus the 3.40 term above with 10 credits → (3.50 × 30 + 34.0) ÷ 40 = 3.475. A strong semester moves a long history slowly — recovery takes consistency, not one heroic term.

Percentage grades

If your school grades in percentages, convert first using its published bands. A common scale: 93+ = A, 90–92 = A−, 87–89 = B+, 83–86 = B, 80–82 = B−, and so on down. Bands vary by school, so verify against your syllabus before converting; a “87 = B+” assumption is right most places and wrong in a few.

Let the calculator do the arithmetic

The GPA Calculator handles all of the above live: add a row per course, pick letter grades or switch to percentage mode, and read your semester GPA with a per-grade breakdown. Enter your previous GPA and credits and it computes the new cumulative too. It runs entirely in your browser — your grades go nowhere.

While you are planning the semester, two neighboring tools are handy: the Reading Time Calculator to budget study material, and the Citation Generator when those papers come due.