How GPA Works: The 4.0 Scale, Weighted vs Unweighted, and Letter-to-Point Math

The first time a scholarship form asked me for my "cumulative GPA on a 4.0 scale," I stared at it for a while. My transcript listed letter grades and credit hours, not a single tidy decimal. I had a vague sense that an A was a 4 and a C was a 2, but I had no idea what my credit-heavy lab courses did to the average, or whether I was supposed to weight anything at all. It turns out the math is simple once you see it laid out, and the part that trips most people is not the arithmetic — it's knowing which average the form actually wants.

This guide walks through the whole thing: how the 4.0 scale assigns points to letters, why credit hours matter, the real difference between a weighted GPA and a plain average, and how to sanity-check a number before you trust it on an application.

The 4.0 scale: turning A, B, C into points

On the standard US 4.0 scale, each letter grade is worth a fixed number of grade points. The plus and minus modifiers shift the value up or down by 0.3 or 0.4. Here is the mapping most US registrars use, with the typical percentage band behind each letter:

| Letter | Grade point | Percentage band | |--------|-------------|-----------------| | A | 4.0 | 93–100 | | A− | 3.7 | 90–92 | | B+ | 3.3 | 87–89 | | B | 3.0 | 83–86 | | B− | 2.7 | 80–82 | | C+ | 2.3 | 77–79 | | C | 2.0 | 73–76 | | C− | 1.7 | 70–72 | | D | 1.0 | 60–69 | | F | 0.0 | below 60 |

Source: this is the grade-point table published by most US university registrars (for example, the standard scales documented by Cornell and the University of Texas), and it is the same band table that evaluation services like WES apply when they convert a foreign transcript. Two things are worth flagging. First, an A and an A+ are both 4.0 on this scale — the plain 4.0 system caps at 4.0, so a perfect score and a 93 land in the same place. (A separate 4.3 scale rewards A+ at 4.3; more on that below.) Second, the bands are not universal. Some schools cut A− at 90, others at 89.5. When a borderline grade matters, check your own institution's published table rather than assuming.

Weighted vs unweighted: the difference that actually changes your number

This is the part the scholarship form never explains. There are two ways to average your grade points, and they can produce noticeably different numbers.

An unweighted GPA is the plain arithmetic mean: add up the grade points for each course and divide by the number of courses. A 1-credit seminar counts exactly as much as a 4-credit chemistry sequence. It is easy to compute and almost never what a registrar reports.

A weighted GPA multiplies each course's grade point by its credit hours, sums those products, and divides by the total credit hours:

Weighted GPA = Σ(grade point × credits) ÷ Σ(credits)

A 4-credit A pulls your average up four times as hard as a 1-credit A. This is how nearly every official transcript is computed, because it reflects how much of your time and academic load each course represented. The word "weighted" here is about credit hours — not to be confused with the high-school sense, where "weighted" means AP and honors courses add an extra point on a 5.0 scale. On a college transcript, weighting means credit-weighting.

If your form asks for cumulative GPA and doesn't specify, assume it wants the credit-weighted figure, because that is the number on your official record.

A worked example: where the two numbers diverge

Numbers make this concrete. Suppose you took four courses this term:

| Course | Grade | Letter point | Credits | |--------|-------|--------------|---------| | Organic Chemistry | A | 4.0 | 4 | | Calculus II | B+ | 3.3 | 4 | | Intro Statistics | B | 3.0 | 3 | | Music Appreciation | C | 2.0 | 1 |

The unweighted GPA is just the average of the four points:

(4.0 + 3.3 + 3.0 + 2.0) ÷ 4 = 12.3 ÷ 4 = 3.075

The weighted GPA multiplies each point by its credits first:

(4.0×4) + (3.3×4) + (3.0×3) + (2.0×1) = 16.0 + 13.2 + 9.0 + 2.0 = 40.2
Total credits = 4 + 4 + 3 + 1 = 12
Weighted GPA = 40.2 ÷ 12 = 3.35

The weighted number (3.35) is higher than the unweighted one (3.075), because your weak grade was in a 1-credit course that barely counts, while your A sits in a heavy 4-credit course. Flip the credits — make Music Appreciation the 4-credit course and Organic Chemistry the 1-credit one — and the weighted GPA drops below 2.9. That swing is the whole reason registrars weight by credits, and it's why quoting the unweighted mean on an application can leave you with a number that doesn't match your official transcript.

You can run your own transcript through this exact calculation with the GPA Calculator: enter each course with its credits and percentage, and the weighted and unweighted figures appear side by side as you type, so the gap between them is visible instead of theoretical.

Converting a non-4.0 transcript

If your grades come on a percentage scale — a Chinese 100-point transcript, say — there is no single official conversion. Receiving schools and evaluation services each pick a method. The two common approaches are a coarse band table (90–100 maps to 4.0, 80–89 to 3.0, 70–79 to 2.0, 60–69 to 1.0) and a continuous formula such as Peking University's, where for a score x ≥ 60 the grade point is 4 − 3 × (100 − x)² ⁄ 1600. The two methods can differ by 0.2 to 0.4 on the same transcript, so report whichever method the application names, and if it stays silent, use the band table and state your method. Evaluation services recompute, and a silent choice of the higher number reads as inflation.

If you only need to convert raw scores between scales rather than build a full GPA, a general-purpose percentage calculator handles the band-to-band arithmetic quickly.

Three checks before you trust the number

A few habits keep your GPA honest:

Confirm which average you reported. The big figure should be credit-weighted. If you accidentally quote the unweighted mean, it won't match your registrar's record.
Check that every counted course has credits above zero. A row with blank or zero credits is dropped from the math entirely — that's correct for audit and pass/fail courses, but a real course missing its credit value silently inflates or deflates your result.
Verify a borderline letter against the band table. An 89.5 that rounds to 90 jumps from B+ (3.3) to A− (3.7), and in a 4-credit course that single rounding decision is worth real points. Knowing the exact value is the number to cite if you email a professor about it.

Get those three right and your GPA will survive a registrar's recomputation, which is the only test that matters when an admissions reader is on the other end.

Made by Toolora · Updated 2026-06-13