Grade Curve Calculator
Calculate grade curve using your data.
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What this tool does
Calculate grade curve using your data. Curves are capped at 100%. Which curve (if any) applies is your instructor's decision — the square-root curve lifts low scores most, the flat curve lifts everyone equally, and the linear curve scales in proportion to the raw score.
How to use the Grade Curve Calculator
- Enter or select raw score (%).
- Enter or select flat curve — points to add.
- Enter or select class mean (%) — for the linear curve.
- Enter or select desired class mean (%) — for the linear curve.
- Read the calculated result; change any measurement to compare alternatives.
Formula
flat curve = raw + points (capped at 100); square-root curve = 10 × sqrt(raw) for a 0–100 score; linear curve = raw × desired mean / class mean (capped at 100)
- score
- Raw score (%)
- flat
- Flat curve — points to add
- classMean
- Class mean (%) — for the linear curve
- desiredMean
- Desired class mean (%) — for the linear curve
Curves are capped at 100%. Which curve (if any) applies is your instructor's decision — the square-root curve lifts low scores most, the flat curve lifts everyone equally, and the linear curve scales in proportion to the raw score.
Worked example
For grade curve calculator, the following measurements illustrate the exact method: Raw score (%): 78; Flat curve — points to add: 5; Class mean (%) — for the linear curve: 70; Desired class mean (%) — for the linear curve: 80.
Inputs
- Raw score (%)78
- Flat curve — points to add5
- Class mean (%) — for the linear curve70
- Desired class mean (%) — for the linear curve80
Result
- Square-root curve (%)88.32
- Flat curve (%)83
- Linear curve (%)89.14
- Raw score (%)78
Results explained
- Square-root curve (%)
- Square-root curve (%) from the formula above. Curves are capped at 100%. Which curve (if any) applies is your instructor's decision — the square-root curve lifts low scores most, the flat curve lifts everyone equally, and the linear curve scales in proportion to the raw score.
- Flat curve (%)
- Flat curve (%) from the formula above. Curves are capped at 100%. Which curve (if any) applies is your instructor's decision — the square-root curve lifts low scores most, the flat curve lifts everyone equally, and the linear curve scales in proportion to the raw score.
- Linear curve (%)
- Linear curve (%) from the formula above. Curves are capped at 100%. Which curve (if any) applies is your instructor's decision — the square-root curve lifts low scores most, the flat curve lifts everyone equally, and the linear curve scales in proportion to the raw score.
- Raw score (%)
- Raw score (%) from the formula above. Curves are capped at 100%. Which curve (if any) applies is your instructor's decision — the square-root curve lifts low scores most, the flat curve lifts everyone equally, and the linear curve scales in proportion to the raw score.
Frequently asked questions
flat curve = raw + points (capped at 100); square-root curve = 10 × sqrt(raw) for a 0–100 score; linear curve = raw × desired mean / class mean (capped at 100)
Curves are capped at 100%. Which curve (if any) applies is your instructor's decision — the square-root curve lifts low scores most, the flat curve lifts everyone equally, and the linear curve scales in proportion to the raw score.
Enter numbers only, in the units and format each label describes. Remove missing values rather than substituting zero, unless zero is a real observation.
No. Results describe the numbers you entered. Statistical inference also depends on sampling design, independence, model fit and interpretation; a p-value is not the probability that a hypothesis is true.
No. Every calculation, including the distribution algorithms, runs entirely in your browser.