GPA is based on letter grades, not raw percentages. Each letter grade you earn in a course is converted to a point value on a numerical scale (usually 0 to 4.0), and your GPA is the average of those point values across all your courses. Your percentage score matters only in determining which letter grade you receive. Once that letter grade is assigned, the percentage itself drops out of the GPA calculation.
How Letter Grades Become GPA Points
Every school maps letter grades to a fixed number of grade points. On the standard unweighted 4.0 scale, the mapping looks like this:
- A (90–100%): 4.0
- B (80–89%): 3.0
- C (70–79%): 2.0
- D (roughly 65–69%): 1.0
- F (below 65%): 0.0
This is the simplest version of the scale, where only whole letter grades exist. Under this system, a student who earns a 91% and a student who earns a 99% both receive an A, both get 4.0 grade points, and both contribute identically to the GPA. The percentage difference between them is invisible once the letter grade is recorded.
Why Plus and Minus Grades Add Nuance
Many colleges and high schools use plus/minus grading, which creates finer distinctions within each letter. Instead of lumping all A-range scores into a single 4.0, a school using plus/minus grades might assign points like this:
- A (93–100%): 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 (60–66%): 1.0
- F (below 60%): 0.0
This makes percentages matter a bit more, because a 92% (A-, 3.7) and a 93% (A, 4.0) now produce different grade points even though they’re only one point apart. But your GPA is still calculated from the letter grade you land on, not from the percentage itself. An 83% and an 86% are both a B and both worth 3.0.
The exact percentage cutoffs for each letter grade vary by school. Some schools set the A/B boundary at 90%, others at 93%. The grade point values for each letter (4.0 for an A, 3.7 for an A-, etc.) are far more standardized, but even those can differ slightly. Always check your own school’s grading policy if you need to calculate your GPA precisely.
How GPA Is Actually Calculated
Once every course has a letter grade and a corresponding point value, your GPA is a credit-weighted average. Multiply each course’s grade points by the number of credits that course carries, add up all those products, then divide by your total credits. For example, if you take a 3-credit course and earn an A (4.0) and a 4-credit course and earn a B+ (3.3), your GPA would be:
(4.0 × 3) + (3.3 × 4) = 12.0 + 13.2 = 25.2, divided by 7 total credits = 3.6 GPA.
Notice that your raw test scores, homework percentages, and exam averages never appear in this formula. They influenced the letter grade your professor or teacher assigned, but the GPA calculation itself only sees the letter and the credit hours.
Weighted GPA in High School
High schools often use a weighted GPA scale that rewards students for taking harder courses. The letter grade still drives the calculation, but the point value for that letter grade increases depending on the course level. A common weighting system adds 0.5 points for honors courses and 1.0 point for AP courses:
- A in a regular class: 4.0
- A in an honors class: 4.5
- A in an AP class: 5.0
A B in an AP course (4.0 weighted) is worth more grade points than a B in a standard course (3.0). This is why some students carry GPAs above 4.0. The underlying mechanism is the same, though: the letter grade is the input, and the course level determines how many points that letter is worth.
When Percentages Do Show Up
Some international grading systems, particularly in countries like India, Canada, and parts of Europe, report academic performance as a percentage or a percentage-based score rather than converting to a 4.0 GPA. If you’re applying to a U.S. college or graduate program with an international transcript, the admissions office or a credential evaluation service will typically convert your percentage into the 4.0 scale using a conversion chart. These charts map percentage ranges to letter-grade equivalents (for example, 90–92% to a 3.7, 87–89% to a 3.3), and the converted letter grade is what produces your GPA.
Within the U.S. system, percentages live inside each course. Your teacher uses them to decide whether your work earns an A, a B+, or a C. But once the grade is on your transcript as a letter, that letter is what counts toward your GPA. Two students with a 94% and a 98% in the same course will have the same GPA impact if both scores fall within the A range at their school.