Grade Curve Calculator

“The professor is curving the exam” is not one statement, it is five. The same raw 64 becomes an 80 under a square-root curve and a 69 under five flat points. Which one your instructor means changes your grade by a letter or more, so it is worth asking rather than assuming.

Read the bell column carefully. At 90 it returns 95, but only because this example class averaged 70 and the target was set higher. Set a target below the actual class average and that whole column moves down instead — the bell curve is the one method here that can cost you points.

The formula is sqrt(score) x 10. A 36 gains 24 points, a 64 gains 16, an 81 gains 9, and a 100 gains nothing.

That taper is the whole design. Because the top of the scale is a fixed point, an instructor can apply it to every student without anyone losing marks and without anyone exceeding 100. It compresses the class upward, which also means it narrows the gap between a struggling student and a strong one — the trade-off people rarely mention.

A bell curve converts each score into a z-score — how many standard deviations it sits from the class average — then rebuilds the class around a new target average, keeping the same spread.

Say the class averaged 70 with a standard deviation of 14.14, and the instructor wants an average of 75. A student who scored 80 was 0.71 deviations above the mean, so they land 0.71 deviations above 75 — an 85. Someone exactly at 70 lands exactly on 75.

If the class had averaged 82 and the target were 75, every one of those movements reverses. This is why a curve is not automatically good news, and why a tool that only ever shows gains would be lying to you.

Flat points add the same number to everyone. It is the most common real-world curve because it is the easiest to explain and nobody's rank changes.

Scale to top multiplies every score by 100 / highest, so the best paper in the room defines full marks. It only helps when the top score was below 100, and it widens the absolute gap between students — doubling a score doubles the distance between any two of them.

Linear interpolation stretches the class range onto a target range, so the lowest score lands on a floor you choose and the highest lands on 100. It is the most aggressive of the three when the class range is narrow.

Canvas does not curve anything on its own, and there is no button a student can press. The percentage in your gradebook is the raw weighted calculation across your assignment groups — which is what the Canvas grade calculator reproduces.

A curve appears only when your instructor edits scores, applies a fudge adjustment, or changes the grading scheme. So the useful move is to work out what a proposed curve would do before grades are final. If you want to test a hypothetical score on an upcoming assignment rather than a curve on a past one, the what-if grade calculator is the right tool.

Switch to Whole class and paste a column of scores — commas, spaces or one per line all work. You get the average, median, spread and pass rate before and after, plus a per-student table.

Blank cells and text like “excused” are ignored rather than counted as zero. That distinction matters more than it sounds: a handful of blanks read as zeros would drag the mean down and change every z-score in a bell curve, quietly handing out a bigger curve than intended.

Watch the spread figure as much as the average. Scale-to-top and linear widen it, the square root curve compresses it, and flat points leave it untouched. If your goal is to lift a struggling cohort without flattening the distinction between the top students, the spread column is where you will see that trade-off.