Study & writing
Curved grade calculator
Enter your raw score and a reference figure, pick a curving method and see the curved grade it produces.
Top score and flat methods use the class top score and the flat points. The mean method uses the class mean in the first box and your target mean in the second.
Three ways to curve a grade
A grading curve adjusts raw scores upward (or occasionally down) so the final marks fit a chosen standard. This tool offers the three methods teachers use most. The top-score method adds the gap between 100 and the highest score to everyone: curved = raw + (100 − top score). The flat-add method gives every student the same fixed number of extra points: curved = raw + points. The mean-to-target method shifts the class so its average lands on a target: curved = raw + (target mean − class mean). Every method here is linear, so the order of students never changes, and all results are capped at 100%.
Worked example with the top-score method: your raw score is 72% and the highest score in the class is 88%. The boost is 100 − 88 = 12 points, so your curved score is 72 + 12 = 84%, a B. The student who scored 88 is lifted to a perfect 100, and everyone else moves up by the same 12 points.
| Raw score | Curved (top score 88) |
|---|---|
| 40% | 52% |
| 55% | 67% |
| 70% | 82% |
| 85% | 97% |
| 100% | 100% |
Choosing a method and reading the result
The top-score method is the gentlest and the most common: it rewards the class for a hard test without changing anyone's rank, and it guarantees at least one perfect paper. Its weakness is that a single high outlier makes the curve tiny for everyone else. The flat add is honest and predictable but arbitrary, since the number of points is chosen by the instructor rather than by the data. The mean-to-target method is the fairest when a test comes out unusually easy or hard, because it anchors the class average to a standard the department expects, but it needs both the real class mean and the target to be entered correctly.
A curve cannot fix a test that was poorly written, and it does not change what you actually learned. Because scores are capped at 100, strong students gain less than weaker ones under a flat or top-score curve, which compresses the top of the range. If the curved result still falls short of the grade you want, the honest next step is to ask the instructor how, and whether, the course is curved, rather than assuming any single method applies.
Frequently asked questions
How do you curve a grade using the highest score?
Subtract the top score from 100 and add that to every student. If the top score is 88, everyone gains 12 points, so a raw 72 becomes 84 and the 88 becomes a perfect 100.
What is a flat-add curve?
A flat curve adds the same fixed number of points to every score, for example +5 to all. It is simple but the amount is chosen by the instructor rather than calculated from the results.
Does a curve ever lower a grade?
It can. A mean-to-target curve that shifts a high class average down, or a strict bell curve, may reduce some scores. The top-score and flat-add methods only raise them.