Grade Curve Calculator
Enter your raw score and choose a curving method to see your curved grade — either bringing the class's highest score up to 100 and adding the same boost to yours, or applying the classic square-root curve.
How the Grade Curve formula works
Two common curving methods:
Highest-score method: Curved score = Your score + (100 − Highest score in class) Square-root method: Curved score = √(Your score) × 10
The square-root method only works on scores expressed out of 100, and boosts lower scores proportionally more than higher ones.
Step-by-step calculation
- For the highest-score method: subtract the class's top score from 100 to find the curve amount, then add that to every score.
- For the square-root method: take the square root of your percentage score, then multiply by 10.
Worked example
Highest-score method: if the top score in class was 92, the curve adds 8 points to everyone — a 75 becomes an 83. Square-root method: a raw score of 64 becomes √64 × 10 = 80.
Frequently asked questions
Which curving method is more common?
The highest-score method (bringing the top score to 100) is more common in most US classrooms since it's simple and transparent. The square-root method is a specific technique that shows up more often in certain math and science courses.
Does a curve ever lower a grade?
With the highest-score method, no — every score only goes up (assuming the highest score is below 100). With the square-root method, scores already above 100 aren't possible, and any score below 100 will be curved upward, since square-rooting a fraction between 0 and 1 always increases it.