Grading on a curve means adjusting raw scores upward using a consistent rule, usually because an exam turned out to be harder than expected. There isn't one universal curving method — instructors use several different formulas, and the same raw score can end up quite different depending on which one is used. This calculator lets you check all three of the most common methods against your own raw score.
The three most common curve 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
Because each method distributes the same 'total curve' differently across the class, a curve that helps a struggling student the most under one method might barely move a top student, and vice versa under a different method. That's exactly why the By Curve Method tab shows all three side by side — it's the quickest way to see which formula a syllabus is actually describing when it just says 'the exam will be curved.'
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.