Grade Curve Calculator
Apply a grading curve to class scores and see each adjusted score and letter grade.
About the Grade Curve Calculator
Paste the class scores, choose a curve method and, where needed, a target or a number of points. The calculator shows each student's new score and letter grade and the new class average.
Teachers curve grades when a test turned out harder than intended. Adding points equally keeps the spread; the square-root curve (10√x) lifts low scores most; shifting to a target average sets the class mean.
The formula
Square-root curve: new = 10 × √original
Worked example
Ten scores from 45 to 88, average 69.4
- Top score to 100: everyone gains 12 points; average 81.4
- Square-root curve: 45 → 67.1, 88 → 93.8; average 82.99
Questions people ask
Which curve is fairest?
Adding the same points keeps everyone's relative standing; the square-root curve helps struggling students most.
Can a curve lower grades?
Not with these methods, unless the target average is below the current one.
Are scores capped?
Yes, at 100.