What Grade Is 30 out of 40?
30 out of 40 is 75% — a C on the standard US scale, a satisfactory score.
- Percentage75%
- Letter gradeC
- Missed10 pts
- For an A (90%)36/40
Score breakdown for a 40-point test
| Score | Percent | Letter |
|---|---|---|
| 36/40 | 90% | A- |
| 32/40 | 80% | B- |
| 28/40 | 70% | C- |
| 30/40 | 75% | C |
How this is calculated
Divide the points earned by the points possible and multiply by 100: 30 ÷ 40 × 100 = 75%. On the common 10-point-band scale that lands in the C range — you'd have needed 36/40 to reach the A band.
Common questions
How are letter grades calculated from percentages?
Most US schools map percentages to letters in 10-point bands: 90–100 is an A range, 80–89 a B range, 70–79 a C range, 60–69 a D range, and below 60 an F. Plus/minus splits each band roughly in thirds (e.g. 90–92 = A-, 93–96 = A, 97+ = A+). Individual schools and professors can and do vary the cutoffs.
What's the difference between weighted and unweighted averages?
An unweighted average treats every score equally: add them up, divide by the count. A weighted average multiplies each category by its share of the grade first — homework 20%, midterms 40%, final 40% — which is how most courses actually work. If your syllabus lists category percentages, you need the weighted version.