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Grading Curve Calculator

Apply grading curves including flat scaling, square root curve, and bell curve. Adjust class grades to desired average.

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Formula

Curved Grade = √(Original Grade × 100) or other curve formulas

Example

original Grade:64
curve Type:square-root
curved Grade:80
improvement:16

Frequently Asked Questions

Square root curve: √(Original × 100). This helps lower scores more than higher ones. Example: 64% becomes √(64 × 100) = √6400 = 80%. A 49% becomes √4900 = 70%. It's generous to struggling students.

A flat curve adds the same points to everyone. If the highest score was 85/100, add 15 points to all students. Fair but doesn't change the relative distribution. Student with 70 becomes 85, student with 40 becomes 55.

Determine your target average (e.g., 75%) and actual average (e.g., 65%). For flat curve: add the difference (10 points). For scaling: multiply all grades by (Target / Actual) = 75/65 = 1.154.

It depends on perspective. Pros: compensates for unexpectedly difficult tests, maintains consistent standards. Cons: can reward poor performance, may demotivate high achievers. Most fair when the test difficulty was misjudged.

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Last updated: 2025-11-13