The 4.0 GPA Scale Explained: Letter Grades, Percentages, and the Math

The 4.0 scale is the standard US grade-point system, used by virtually every high school and college in the country for unweighted GPAs. The idea is simple: convert each letter grade to a number between 0.0 and 4.0, average them across all your classes (weighted by credit hours), and call that your GPA.

The execution is messier than the idea, because schools disagree on three things — whether to use plus/minus modifiers, how to handle A+ at the top, and what percentage cutoffs map to which letters. This post lays out the full standard scale, the most common variations, and where the edge cases come from.

The 50-word version

The 4.0 GPA scale maps letter grades to grade points: A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0.0. Plus/minus modifiers add ±0.3 (so A− = 3.7, B+ = 3.3). Most colleges treat A+ as 4.0 — only a minority give it 4.3 — making 4.0 the practical ceiling.

The full standard chart

This is the standard 4.0 scale used by most US schools and accepted by virtually every college admissions office:

Letter Grade	Percentage	GPA Points
A+	97–100	4.0 (some schools 4.3)
A	93–96	4.0
A−	90–92	3.7
B+	87–89	3.3
B	83–86	3.0
B−	80–82	2.7
C+	77–79	2.3
C	73–76	2.0
C−	70–72	1.7
D+	67–69	1.3
D	63–66	1.0
D−	60–62	0.7
F	Below 60	0.0

The percentage cutoffs are conventions, not laws. A few state systems (notably some districts in California and Texas) use 90–100 = A, 80–89 = B, 70–79 = C, 60–69 = D, with no plus/minus. Some use 93–100 = A. The cutoff your school uses determines where the boundaries sit, but the GPA point values are nearly universal once a letter grade is assigned.

How to read the math

A 4.0 GPA = straight A's, every class, no exceptions. A 3.5 GPA usually means a mix of A's and B's. A 2.0 GPA = straight C's.

The formula:

GPA = sum(grade points × credit hours) / sum(credit hours)

Worked example. A high school student has:

Course	Grade	Points	Credits
English	A	4.0	1
Algebra	B+	3.3	1
US History	A−	3.7	1
Biology	A	4.0	1
Spanish	B	3.0	1
Art	A	4.0	1

Sum of (points × credits) = 4.0 + 3.3 + 3.7 + 4.0 + 3.0 + 4.0 = 22.0

Sum of credits = 6

GPA = 22.0 / 6 = 3.67

For college courses, the math is identical but each course is usually worth 3 or 4 credit hours, so each grade carries more weight. A 4-credit A counts more than a 3-credit B in the final average. Run any combination through the unweighted GPA calculator and it'll handle the credits.

The A+ controversy

Most US schools — including most Ivies and selective colleges — treat A+ as 4.0, not 4.3.

The reasoning: the unweighted scale exists to give a "perfect" ceiling number that's comparable across institutions. If some schools let A+ produce a 4.3 GPA, then a transcript with mostly A's and a few A+ could mathematically exceed 4.0. That defeats the comparability purpose.

A minority of schools — notably Stanford, Caltech, a few private high schools — do permit GPAs above 4.0 unweighted by treating A+ as 4.3. On those transcripts a "perfect" student can have a 4.15 or 4.2 unweighted GPA. Outside this minority, the convention is A+ caps at 4.0.

When you fill out the Common App and it asks for your unweighted GPA "out of 4.0," the answer is 4.0 max — not 4.3 — even if your school's transcript lists A+ as 4.3.

Plus/minus vs no plus/minus

About 70% of US high schools use the full plus/minus scale shown in the table above. The other 30% use a simpler version where:

Letter	Points
A	4.0
B	3.0
C	2.0
D	1.0
F	0.0

No A− at 3.7, no B+ at 3.3. Just whole numbers.

This produces some interesting comparison effects. A student who got A−'s in every class on a plus/minus scale ends with a 3.7 GPA. The same student on a no-plus/minus scale (where A− is just an A) ends with a 4.0.

College admissions offices know this and recompute when needed. The Common App asks specifically about your school's GPA scale precision so they can normalize.

If your school uses plus/minus and a Common App question is asking for unweighted GPA, give the number from your transcript with the precision your school uses. The college will normalize from there.

How the 4.0 scale compares internationally

The 4.0 scale is a US convention. Most other countries don't use it.

Country	Native scale	Rough US 4.0 equivalent
United Kingdom	First / 2:1 / 2:2 / 3rd	First ≈ 4.0, 2:1 ≈ 3.3–3.7
Canada	4.0 or 4.3 or percentage	Direct mapping
Australia	High Distinction (HD) / Distinction (D)	HD ≈ 4.0, D ≈ 3.5
Germany	1.0 (best) to 5.0 (fail)	1.0–1.5 ≈ 4.0
France	0–20 (16+ excellent)	16–20 ≈ 4.0
India	10-point CGPA	9+ ≈ 4.0

WES (World Education Services) is the standard credential evaluator for international transcripts. If you're applying from a non-US system to US grad school, the WES evaluation produces a single 4.0-scale GPA from your foreign transcript.

For converting common European percentages, the percentage to GPA calculator handles the standard US mapping (90+ = A = 4.0). For UK to US conversion specifically, the classification matters more than the percentage.

The high school vs college 4.0 difference

The grade-point values are the same, but the GPA math differs in one important way: credit hours.

In high school, most courses are 1 credit per semester. A student takes 6–7 courses per semester. All grades weigh roughly equally in the GPA calculation.

In college, each course is 3–4 credit hours (sometimes 5 for science with lab, 6+ for senior projects). A student takes 12–18 credit hours per semester. The math is the same — credit-weighted average — but a heavy course pulls more weight.

Worked example. A college student's semester:

Course	Credits	Grade	Points
Calculus II	4	B+	3.3
Organic Chem (with lab)	5	A−	3.7
English Lit	3	A	4.0
History	3	B	3.0

Total grade points = (4 × 3.3) + (5 × 3.7) + (3 × 4.0) + (3 × 3.0) = 13.2 + 18.5 + 12.0 + 9.0 = 52.7

Total credits = 15

GPA = 52.7 / 15 = 3.51

The 5-credit Organic Chem class with the A− has more impact than the 3-credit English class with the A. This is why college students obsess over the "heavy" courses.

Use the college GPA calculator to model your transcript — it handles the credit-hour math automatically.

Edge cases and exceptions

A few things people get wrong about the 4.0 scale:

Pass/Fail courses don't count toward GPA. A "P" on your transcript is not 0 grade points and not 4 grade points — it's excluded from the GPA calculation entirely. Same for "Audit" or "Withdraw" notations.

Repeated courses depend on policy. If you retake a class, some schools (and most colleges that practice grade replacement) replace the original grade entirely. Others average the two. Check your school's grade replacement policy.

Withdrawals (W) usually don't affect GPA but do affect transcripts. A W stays on your record but doesn't enter the GPA math. Too many W's flag a "completion" concern at grad school applications even though the GPA looks fine.

Incompletes (I) eventually convert. An I that becomes a permanent grade enters the GPA at that grade's value. An I that stays unresolved past the deadline usually becomes an F at most institutions.

Why the 4.0 scale persists

It's been the US convention since the early 1900s. The math is clean (every letter has a defined number), the ceiling is comparable across institutions, and most colleges and employers know how to read it.

The downside is the 4.0 ceiling problem — it can't distinguish among "perfect" students. That's why weighted GPAs exist for high schoolers (to add rigor signal) and why college students rely on a combination of GPA + course difficulty + standardized tests for grad school applications.

For practical use: when in doubt, the 4.0 scale unweighted GPA is the number that almost any US institution will accept and understand. Calculate it once and use it.

FAQ

Is 4.0 the highest possible GPA? For unweighted GPA, yes, at most schools. A minority of institutions treat A+ as 4.3 (Stanford, Caltech, a few high schools), so a "perfect" student there can have a 4.15 unweighted. For weighted GPAs, the ceiling is higher (5.0 or 6.0 depending on the system).

Is a B+ the same as a 3.5 GPA? No. A single B+ grade is worth 3.3 grade points on the plus/minus scale. A 3.5 GPA is a cumulative average — usually a mix of A's, A−'s, B+'s, and B's that averages to 3.5.

Does the 4.0 scale use percentages? Indirectly. Schools first convert percentages to letter grades using their own cutoffs (typically 93+ = A, 90–92 = A−, etc.), then convert the letter to a grade point. The GPA is calculated in grade points, not percentages.

Why do some colleges give A+ a 4.3 and others not? Historical convention. Most schools cap the unweighted scale at 4.0 because it preserves comparability across institutions. A few schools have always allowed 4.3 for A+ and didn't switch when the convention shifted.

Can I have a GPA above 4.0? On the unweighted scale, only if your school treats A+ as 4.3 (uncommon). On the weighted scale, yes — most weighted scales top at 5.0 and some go to 6.0. The weighted GPA calculator shows the weighted ceiling for your school.

Bottom line

The 4.0 scale is the standard US grade-point system: A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0.0, with plus/minus adding or subtracting 0.3 at most schools. A+ typically caps at 4.0, with rare exceptions allowing 4.3. The math is a credit-weighted average — straight A's get you to 4.0, mixed A's and B's land you between 3.0 and 4.0. Use the unweighted GPA calculator for high school transcripts or the college GPA calculator for credit-hour-based college transcripts.