A Curved Grade Calculator
A curve changes the scale, not the ranking. Three methods cover almost every real curve: proportional, square root, and simply adding the same points to everyone.
Proportional curve
86.6667
- Square root curve
- 88.3176
- Points a flat curve would add
- 10
- Score with a flat curve
- 88
Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.
The formula this calculator uses
curved = score / highest x 100
- score
- Your raw mark before any curve
- highest
- The highest raw mark in the class
- curved
- Your mark after the curve is applied
How to check the result by hand
- 1
Find the highest raw score in the class
The proportional and flat curves both key off it. If the best mark was already 100, neither curve changes anything.
- 2
Divide your score by that highest score
78 divided by 90 is 0.8667. This ratio is the proportion of the best performance you achieved.
- 3
Multiply by 100 for the proportional curve
0.8667 becomes 86.7 per cent. Everyone rises by the same factor, so the ranking is untouched.
- 4
Try the square root curve for comparison
Ten times the square root of 78 is 88.3. It is more generous than the proportional curve at this score, and much more generous at low scores.
- 5
Decide the grade boundary before curving
Whether a boundary is applied before or after the curve changes who passes. Settle that question first, then apply the transformation.
For worked examples, common mistakes and the limits of this formula, read the full How To Calculate A Curved Grade page.