Under the most widely used US convention, a plus modifier adds 0.3 grade points and a minus modifier subtracts 0.3 from the base letter grade value — so B+ is 3.3, B is 3.0, and B- is 2.7. A meaningful minority of schools instead use a 0.33 increment (making B+ worth 3.33), and some skip plus/minus grading entirely. There is no single national standard; each institution sets its own scale.
The two most common conventions
| Letter Grade | GPA Points (0.3 increment — most common) | GPA Points (0.33 increment — less common) |
|---|---|---|
| A+ | 4.0 (some schools: 4.3) | 4.0 (some schools: 4.33) |
| A | 4.0 | 4.0 |
| A- | 3.7 | 3.67 |
| B+ | 3.3 | 3.33 |
| B | 3.0 | 3.0 |
| B- | 2.7 | 2.67 |
| C+ | 2.3 | 2.33 |
| C | 2.0 | 2.0 |
| C- | 1.7 | 1.67 |
| D+ | 1.3 | 1.33 |
| D | 1.0 | 1.0 |
| D- | 0.7 | 0.67 |
| F | 0.0 | 0.0 |
Both conventions are attempts to divide the one-point gap between whole letter grades (say, C at 2.0 and B at 3.0) into three steps for minus, plain, and plus. The 0.3 version is simpler to compute by hand but the three increments (0.3+0.3+0.3=0.9) don't perfectly sum to a full point; the 0.33 version divides more evenly but introduces repeating decimals. Neither is objectively correct — it's purely an institutional choice, and the difference between them almost never exceeds a few hundredths of a GPA point on any individual grade.
Why this small difference is worth knowing
A 0.03-point gap on a single course looks negligible, but it compounds across a full transcript. A student with several plus/minus grades across a 30-credit year could see their computed GPA differ by a hundredth or two depending on which increment their school uses — usually not enough to matter for most purposes, but potentially relevant for a borderline scholarship or honors cutoff decided to two decimal places.
It also explains why two GPA calculators, or a student's manual calculation versus their official transcript, can occasionally disagree by a tiny amount on grades that look identical on paper. If your calculated GPA doesn't exactly match your transcript, checking whether your school uses 0.3 or 0.33 increments is one of the first things worth verifying.
Worked example: same grades, two conventions
Consider a semester with these four courses:
| Course | Credits | Letter Grade |
|---|---|---|
| Microeconomics | 3 | A- |
| Organic Chemistry | 4 | B+ |
| Statistics | 3 | C- |
| Studio Art | 2 | B- |
Using the 0.3 increment:
Quality points: (3.7×3)+(3.3×4)+(1.7×3)+(2.7×2) = 11.1+13.2+5.1+5.4 = 34.8
GPA = 34.8 ÷ 12 = 2.90
Using the 0.33 increment:
Quality points: (3.67×3)+(3.33×4)+(1.67×3)+(2.67×2) = 11.01+13.32+5.01+5.34 = 34.68
GPA = 34.68 ÷ 12 = 2.89
The two conventions produced a 0.01 difference here — small, but a real illustration of why the exact increment your school uses matters if you're trying to match a self-calculated GPA to an official transcript figure precisely.
Schools that don't use plus/minus at all
Not every institution grades with modifiers. Some use only whole letter grades — A, B, C, D, F — each worth a flat 4.0, 3.0, 2.0, 1.0, and 0.0 respectively, with no in-between values. This is common at some high schools and a smaller number of colleges. If your school falls into this category, plus/minus conversion tables simply don't apply to you; use the base values directly. Our letter grade to GPA conversion chart covers the base scale in more depth.
Grades that commonly don't get a plus/minus modifier
- A+ at the very top of the scale. Many schools cap A+ at the same 4.0 value as a plain A, since 4.0 is treated as the ceiling. A smaller number extend the scale to 4.3 (see our guide on converting GPA to a 4.3 scale) to give A+ extra value.
- F at the bottom of the scale. Plus/minus modifiers almost never apply to a failing grade — there isn't a meaningful GPA distinction between different degrees of failing at most institutions.
- D- at some schools. A number of institutions treat anything below a D as an automatic F, skipping D- as a distinct grade band entirely.
How to find your school's exact values
Because there's no universal standard, the only fully reliable source is your own institution's official grading policy, typically published by the registrar's office or included in your course catalog. Look specifically for the numeric grade point table, not just a description of the letter grades offered — some catalogs describe the letters (A, A-, B+, etc.) without listing the exact point values nearby, requiring you to cross-reference a separate GPA policy page.
Try it yourself
Once you know which increment your school uses, our GPA Calculator lets you enter grades directly and applies the standard plus/minus values automatically — calculated instantly in your browser, with no account required. If your school uses the less common 0.33 increment, you can adjust individual grade point values as needed to match your institution's exact scale.
