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Grade Curve Calculator

Compare the three common curving methods on the same score before you commit to one.

✓ Updates as you type✓ Works on mobile✓ Nothing is saved

Curve a score

Enter the raw score, then the values each method needs.

Raw score%Flat points to addHighest score in class%

How it works

How to calculate it

A flat curve adds the same number of points to every score. A square root curve takes the square root of the score and multiplies by ten, which lifts low scores far more than high ones. Scaling to the top treats the highest score in the class as 100% and rescales everyone proportionally.

Flat = raw + points · Square root = √raw × 10 · Scaled = (raw ÷ top score) × 100

Worked example

Example calculation

A raw score of 72% becomes 77% with a 5-point flat curve, 84.9% with a square root curve, and 81.8% when scaled against a class high of 88%.

Use the calculator above to substitute your own numbers. Results update immediately.

Before you rely on the number

Things worth checking

The square root curve helps the bottom of the class most: a 36% rises to 60%, while a 90% only rises to 94.9%. Use it when a test was harder than intended across the board.
Scaling to the top score is sensitive to a single outlier. One unusually strong paper compresses the curve for everyone else.
A flat curve preserves the gaps between students exactly, which makes it the easiest method to defend if a grade is challenged.
Grade the papers first with the EZ Grader, then curve the resulting percentages here.

Common questions