There is no universal grading curve. This calculator applies three specified score adjustments, not a bell-curve or percentile distribution. Your syllabus or instructor determines the method, limits, and rounding. All inputs are percentages out of 100, and negative adjustments can reduce grades.
Three supported adjustment methods
The flat-points-added curve is the simplest: the instructor picks a number of points (often derived from how far the top score fell short of 100) and adds it to every student's score. Because it's a flat addition, the gap between students stays exactly the same after curving.
The percentage-boost curve multiplies the raw score by a factor instead of adding a flat amount. A 10% boost turns a 60 into 66 and a 90 into 99 — higher scorers gain more raw points, which is the opposite effect of a flat curve.
The highest-score-to-100 curve (sometimes called curving to the top) rescales every score by the same ratio needed to bring the class's best score up to 100. It rewards students in proportion to how close they were to the top performer, and it's undefined if nobody in the class scored above 0.
Why the same raw score gives different curved results
The same adjustment number does not describe equivalent policies: adding 10 percentage points to 60 gives 70, while a 10% relative boost gives 66. Scaling depends separately on the class high score. Compare methods shows these alternatives, but cannot determine the policy your instructor uses.
Limits and things to double-check
This calculator applies the formula an instructor tells you they're using — it can't determine which curve method your class actually follows, since that's set by the instructor's own grading policy (often stated on the syllabus). If your instructor caps curved scores at 100%, check the 'Cap curved score at 100' box so the preview matches what will show up in the gradebook. And the highest-score-to-100 method needs a real highest score greater than zero to produce a result.