Grade Curve Calculator
Apply different curving methods to class scores and visualize before/after grade distributions.
Enter Class Scores
20 valid scores detected (0–100)
Curve Method
Class Average Before
71.8%
Class Average After
84.3%
Students Moving Up a Grade
17 / 20
Before Curve — Grade Distribution
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3
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4
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5
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3
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5
After Curve — Grade Distribution
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7
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7
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4
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2
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0
Score Comparison Table (first 20)
| # | Original Score | Curved Score | Change |
|---|---|---|---|
| 1 | 72.0% | 84.9% | +12.9 |
| 2 | 65.0% | 80.6% | +15.6 |
| 3 | 88.0% | 93.8% | +5.8 |
| 4 | 45.0% | 67.1% | +22.1 |
| 5 | 90.0% | 94.9% | +4.9 |
| 6 | 78.0% | 88.3% | +10.3 |
| 7 | 55.0% | 74.2% | +19.2 |
| 8 | 83.0% | 91.1% | +8.1 |
| 9 | 61.0% | 78.1% | +17.1 |
| 10 | 95.0% | 97.5% | +2.5 |
| 11 | 70.0% | 83.7% | +13.7 |
| 12 | 48.0% | 69.3% | +21.3 |
| 13 | 76.0% | 87.2% | +11.2 |
| 14 | 82.0% | 90.6% | +8.6 |
| 15 | 59.0% | 76.8% | +17.8 |
| 16 | 91.0% | 95.4% | +4.4 |
| 17 | 67.0% | 81.9% | +14.9 |
| 18 | 74.0% | 86.0% | +12.0 |
| 19 | 86.0% | 92.7% | +6.7 |
| 20 | 52.0% | 72.1% | +20.1 |
Grade Curve Calculator — How to Curve Grades
A grade curve adjusts scores when a test was too difficult or the class average is lower than expected. The square root curve (√score × 10) is the most common — it raises low scores more than high scores (a 64 becomes 80, a 81 becomes 90, a 100 stays 100). Flat point addition simply gives everyone the same bonus. Scale to top score sets the highest score as 100% and adjusts everyone proportionally — fair when students scored well but a test had errors. Standard deviation adjustment normalizes scores around a target mean, preserving relative ranking while shifting the class average.