How to Convert a Percentage to a Letter Grade and GPA

Percentage to GPA Is a Two-Step Conversion

There is no single formula that turns a percentage into a GPA, because two separate tables sit between them. First, your school's grading bands turn a percentage into a letter grade. Second, the GPA scale turns that letter grade into grade points. Doing the steps in order, one course at a time, is what makes the conversion accurate. Skipping ahead, especially by converting an average percentage directly, is where most estimates go wrong.

Step 1: Percentage to Letter Grade

Many US schools and instructors use a band table similar to the one below, where each letter grade covers a 3- or 4-point slice of the percentage range. It is a convention, not a law, so treat it as the default only when your syllabus does not say otherwise.

Step 2: Letter Grade to Grade Points

Once each course has a letter grade, the GPA scale assigns grade points: A is 4.0, A- is 3.7, B+ is 3.3, and so on down to F at 0.0. Multiply each course's grade points by its credit hours, add the results, and divide by total graded credits. That weighted average is the GPA. If your school gives A+ extra value on a 4.3 or 4.33 scale, use that table instead; the mechanics are identical.

Why Averaging Percentages First Gives the Wrong GPA

Here is the trap in numbers. Suppose you took two 3-credit courses and earned 95% in one and 79% in the other. Your average percentage is (95 + 79) / 2 = 87%, and 87% converts to a B+, which is 3.3. So the shortcut says your GPA is 3.3.

Now do it correctly. The 95% converts to an A, worth 4.0. The 79% converts to a C+, worth 2.3. With equal credits, your GPA is (4.0 + 2.3) / 2 = 6.3 / 2 = 3.15. The shortcut overstated your GPA by 0.15, which is enough to matter near a 3.0 or 3.2 cutoff.

The reason is that the band conversion is not linear. Within the A band, a 93 and a 100 earn the same 4.0, while one percentage point at a band edge, say 92 to 93, jumps the grade points by 0.3. Averaging percentages smears scores across those edges, and the error can go in either direction. Converting course by course respects the bands the way your registrar does.

The 10-Point-Band Variant

Plenty of schools and instructors use simpler 10-point bands: 90-100 is an A, 80-89 is a B, 70-79 is a C, 60-69 is a D, and below 60 is an F, sometimes without plus or minus grades at all. Under that table, the same two courses above convert to an A (4.0) and a C (2.0) for a GPA of 3.0, a different answer from the plus/minus table. Same percentages, different bands, different GPA, which is exactly why you cannot convert without knowing which table applies.

When the Syllabus Publishes Its Own Bands

Individual instructors often set their own cutoffs, for example an A at 92.5 or a curve applied at the end of the term. When a syllabus publishes bands, those bands override any generic table for that course. Convert each course using its own syllabus, then combine the resulting grade points into one GPA. Our guide on reading a syllabus grade breakdown shows where those rules usually hide.

Use the Converter, Then the GPA Calculator

The Percentage to Letter Grade Converter handles step one for a single score, including alternate band tables. For a full GPA, convert each course, then enter the letter grades and credit hours in the College GPA Calculatorso the credit weighting is handled for you. If a course's percentage sits within a point of a band edge, run both letter grades through the calculator to see how much the difference actually moves your GPA before you spend energy worrying about it.