Grade Curve Calculator
Curve a set of test scores three ways: add flat points, scale the top score to 100, or apply a square-root curve. Paste your class scores and compare the original and curved averages.
When and why to curve
Curving adjusts a set of scores upward, usually when a test turned out harder than intended. A fair curve preserves the order of students while lifting everyone, rather than rewarding or punishing anyone unfairly. This grade curve calculator offers three common, transparent methods and shows you the effect on the class average before you commit.
Three curve methods explained
Add points gives every student the same flat boost — simple and easy to justify. Top to 100 finds the highest score and lifts everyone by the gap to 100, which helps when even your best student struggled. Square root multiplies the square root of each score by ten, giving a bigger lift to lower scores and a smaller one to high scores, gently compressing the range.
Use curves thoughtfully
A curve should correct a flawed assessment, not mask a teaching gap. Compare the original and curved averages here and choose the gentlest method that achieves a fair result. Once curved, you can drop the new scores into the Weighted Grade Calculator to fold them into final grades.
Frequently Asked Questions
What is the fairest way to curve grades?
There is no single answer, but adding flat points is the most transparent. The square-root method helps struggling students most. Pick the gentlest curve that fixes the problem.
Does the square-root curve cap at 100?
Yes. All methods in this tool cap curved scores at 100 so no one exceeds full marks.
Will curving change the ranking of students?
No. Every method here preserves the original order of students; it only shifts the scores upward.
Is the tool free?
Yes, free and private — your scores never leave your browser.