Curve Test Calculator

Apply grade curves in seconds:

Enter the raw score. Type the original test score (out of 100 or your custom maximum).

Choose a curving method. Select from flat-point addition (add fixed points), percentage bump (increase by a percentage), or square root curve (takes the square root and multiplies by 10).

Configure parameters. For flat-point addition, set how many points to add. For percentage bump, set the percentage increase.

View curved results. The calculator displays the original score, the curved score, and the point difference. Scores are automatically capped at the maximum (typically 100).

Each curving method has different effects on score distributions:

Flat-Point Addition: Adds a fixed number of points to every score. Simple and equal — everyone gets the same boost. Best when the entire class performed below expectations by a similar margin.

Percentage Bump: Increases each score by a percentage of the raw score. Students with higher scores get a larger absolute boost. This maintains relative performance differences.

Square Root Curve: Applies the formula: curved = √(raw) × 10. This method gives the largest boost to the lowest scores and progressively less help to higher scores. A raw 49 becomes 70, while a raw 81 becomes 90. It's the most commonly used method for normalizing difficult exams.

Apply curves responsibly:

• Analyze the distribution first — Before curving, look at the class average and standard deviation. A curve is most justified when the median score is well below expectations.
• Be consistent — Apply the same curve to all students in the same section.
• Document your method — Transparency builds trust. Share which method you used and why.
• Consider the square root curve — It's often the fairest option as it helps struggling students the most while still rewarding high performers.