How do you read a grading scale?
Look for the lowest percentage that earns each letter. Most scales are really lists of cutoffs: 90% or above is an A on one scale, 93% or above is an A on another. Everything between one cutoff and the next belongs to the lower letter. Start with the published cutoff in your syllabus, student handbook, or gradebook, then compare your exact percentage against it.
The common detailed (plus and minus) scale
This is a common US reference, not a universal standard. Ranges are shown as whole numbers; a score of 86.4% still counts as a B because it is at least 83 and below 87.
| Letter | Minimum % | Letter | Minimum % |
|---|---|---|---|
| A+ | 97 | C+ | 77 |
| A | 93 | C | 73 |
| A- | 90 | C- | 70 |
| B+ | 87 | D+ | 67 |
| B | 83 | D | 63 |
| B- | 80 | D- | 60 |
Below 60% is an F on this scale. The full reference, with ranges and 4.0 grade points, is on our grading scale page.
The same score on three scales
Here is one course grade of 91% on three scales. The percentage is identical; only the letter moves.
| Scale | Cutoffs | Letter for 91% |
|---|---|---|
| Standard A+ to F | A- starts at 90 | A- |
| Simple A to F | A 90, B 80, C 70, D 60 | A |
| Custom example | A 93, B 83, C 73, D 63 | B |
That gap between an A and a B is why you should never copy a letter from a chart that is not yours. In our tools you can switch between these scales, or enter your own cutoffs, and watch the letter change while the percentage stays put. Try it in the Class Grade Calculator or the Easy Grader.
Plus/minus, rounding, and boundaries
- Rounding. Some instructors round 89.5% up to 90%. Others use the exact value, so 89.9% stays a B+. Our calculators use the exact value.
- Inclusive cutoffs. A cutoff of 90 usually means 90.00% and above earns that letter.
- Missing letters. Some schools have no A+ or no D-, so the top or bottom of the table looks different.
Letter grade versus GPA points
A grading scale gives you a letter. A GPA scale is a second, separate table that assigns points to each letter, often 4.0 for an A and 3.3 for a B+. Schools also differ here, for example in how they treat an A+. Use your registrar's table for anything official, and see the note on GPA conversion on the grading scale page.
Common mistakes
- Assuming every school uses the same cutoffs. They do not.
- Reading a range as a whole-number gap. 86.5% is inside the B range, not between B and B+.
- Confusing the percentage with the letter. Calculate the percentage first, then read the letter.
- Forgetting curves. If the instructor curves scores, apply the curve before you read the scale.
Special cases
Some courses set a higher minimum for the whole course to count as passing. Programs and majors may require a C or better even when a D earns credit in general. Pass/fail courses use a single cutoff instead of a scale. When in doubt, ask your instructor which rule applies.
For the calculation that comes before the scale, read how to calculate a test grade and how to calculate your current grade. To convert a single score, use the Test Grade Calculator.