A grade curve adjusts raw scores to achieve a desired distribution or to account for test difficulty. It helps ensure fair grading across different assessments.

Linear Scale: Simple addition/multiplication. Good for uniform adjustments.
Bell Curve: Forces grades into a normal distribution. Use when you want specific mean/standard deviation.
Square Root: Benefits lower scores more than higher ones. Good for difficult tests.
Percentile-Based: Assigns grades based on ranking. Ensures top X% get certain grades.
Custom: Create your own formula for specific needs.

The square root curve takes the square root of the raw score and multiplies it by a factor (usually 10). This gives a bigger boost to lower scores. For example: √64 × 10 = 80, while √81 × 10 = 90.

By default, the calculator caps grades at 100%. However, some educators allow grades above 100% for extra credit scenarios.