A grading scale defines the minimum percentage required for each letter grade. It converts a numerical score into A, B, C, D, or F, often with plus and minus bands.
Percentage to letter-grade table
This reference uses the plus/minus scale included as the calculator’s standard default. It is a useful starting point, but a course syllabus, school district, college, or university may publish different thresholds.
| Letter grade | Minimum | Percentage range | GPA value |
|---|---|---|---|
| A | 93% | 93%–100% | 4.0 |
| A− | 90% | 90%–92.99% | 3.7 |
| B+ | 87% | 87%–89.99% | 3.3 |
| B | 83% | 83%–86.99% | 3.0 |
| B− | 80% | 80%–82.99% | 2.7 |
| C+ | 77% | 77%–79.99% | 2.3 |
| C | 73% | 73%–76.99% | 2.0 |
| C− | 70% | 70%–72.99% | 1.7 |
| D+ | 67% | 67%–69.99% | 1.3 |
| D | 63% | 63%–66.99% | 1.0 |
| D− | 60% | 60%–62.99% | 0.7 |
| F | 0% | 0%–59.99% | 0.0 |
What each letter grade means
The percentage range is only half the picture — each letter also carries a practical outcome beyond the number on the page.
What counts as a passing grade?
On the standard scale, anything at or above 60% (a D− or better) generally passes in US high schools. College works differently — a D may technically pass a course, but many prerequisite, major-specific, or financial-aid rules require a C or better. Always confirm the passing threshold in the syllabus rather than assuming 60% applies everywhere.
How to calculate GPA from letter grades
GPA converts letter grades into a single number using grade points and credit hours, not just an average of percentages.
- 1
Convert each grade to points
Use the GPA value column above — A = 4.0, B+ = 3.3, and so on.
- 2
Multiply by credit hours
Each course's grade points × its credit hours gives that course's quality points.
- 3
Add and divide
Sum every course's quality points, then divide by total credits attempted.
Five 3-credit courses graded A, A, B+, B, and C add up to roughly 48.9 quality points across 15 credits — about a 3.26 GPA. Use the GPA calculator to run your own courses and credits instead of doing this by hand.
Weighted grades combine multiple categories
A single percentage only reflects one assignment. Most courses combine several weighted categories — homework, quizzes, exams, a final — into one overall grade before that grade gets mapped to a letter on this scale. Use the gradebook calculator to combine your own categories and see the resulting letter grade.
Grading scales beyond the standard US model
The A–F percentage scale above is common but not universal. Some schools grade on a curve, ranking students against classmates rather than a fixed percentage. The International Baccalaureate uses a seven-point scale instead of letters, and some elementary programs use a 1–4 rating or non-numeric marks like S, N, and U rather than A–F. Always check which system a specific school or course actually uses before comparing scores across institutions.
Transcript codes beyond letter grades
Transcripts often include codes that aren't part of the A–F scale at all.
| Code | Meaning | GPA effect |
|---|---|---|
| W | Withdrew before the deadline | No effect on GPA |
| I | Incomplete; work still outstanding | Excluded until resolved |
| P | Passed a pass/fail course | No effect on GPA |
| XF | Stopped attending without formally withdrawing | Counted like an F (0.0) |
| X | Audited — attended without earning credit | No effect on GPA |
Grading scale for a specific test size
Teachers grading a fixed-length quiz often want the scale for that exact number of questions, since each question is worth 100 ÷ total. These pages give the full wrong-answer-to-letter-grade table for the most common test sizes, ready to print as a marking key.
- Grading scale for 10 questions
- Grading scale for 12 questions
- Grading scale for 15 questions
- Grading scale for 20 questions
- Grading scale for 25 questions
- Grading scale for 30 questions
- Grading scale for 40 questions
- Grading scale for 50 questions
- Grading scale for 60 questions
- Grading scale for 100 questions
Grading scales for teachers
The calculator above ships with three teacher-facing presets. The standard scale puts an A at 93% and a passing D− at 60%. The strict scale raises every threshold by about two points; the lenient scale lowers them by three. Set a custom scale on the grade calculator to match a syllabus exactly, then print the resulting chart as a class marking key.
Compare standard, strict, and lenient scales
| Scale preset | A starts | B starts | C starts | D starts |
|---|---|---|---|---|
| Standard | 93% | 83% | 73% | 63% |
| Strict | 95% | 85% | 75% | 65% |
| Lenient | 90% | 80% | 70% | 60% |
Percentage, letter grade, and GPA are different
A percentage describes points earned out of points possible. A letter grade groups a percentage into a band. GPA converts course grades into grade points and may account for course credits or advanced-class weighting. Because GPA policies vary, use the official school scale for transcript calculations.
Use a custom grade scale
The Grade Calculator tool includes standard, strict, and lenient presets. You can also edit every minimum threshold to match a syllabus or school policy.
Open the custom grade calculator