Proportional / Ratio · “The Fair-to-Effort Curve”
Proportional Grade Curve Calculator
Scale every score by the same factor — the top score reaches the maximum, and the gaps between students stay proportional.
Used by 2,000+ teachers · No signup · 100% private
Why a proportional curve?
A ratio curve multiplies everyone by the same factor so the highest score lands at the maximum. Unlike adding flat points, it keeps the relationships between scores intact — a student who scored twice as high still scores twice as high afterward. It shows there’s a system behind the adjustment, not just a handout.
- Highest score reaches the maximum — the curve is anchored to your top performer.
- Proportions preserved — relative gaps between students don’t change.
- Rewards effort fairly — stronger raw scores keep their lead.
Frequently Asked Questions
What is ratio curving?
Ratio curving scales all scores proportionally so the highest score reaches 100%. If the top score is 85%, every score is multiplied by 100/85, raising everything proportionally.
How does the Ratio Calculator work?
Enter raw scores; the calculator finds the highest score, computes the scaling factor (100 ÷ highest), and multiplies every score by it, keeping relative spacing.
What's the formula for ratio curving?
New Score = (Original Score ÷ Highest Score) × 100. If the highest is 80%, then 80% → 100%, 60% → 75%, 40% → 50%.
When should I use ratio curving instead of linear?
Use ratio when you want the highest score to reach exactly 100% while scaling everyone proportionally. Linear adds the same points; ratio multiplies.
Is ratio curving fair?
Yes. It maintains the original spread proportionally — if one student was ahead before, they stay ahead after. Everyone moves up together.
What's the difference between ratio and bell curve?
Ratio uses the highest score as its reference; bell curve uses the class mean and standard deviation. Ratio is simpler and more direct; bell curve is more statistically rigorous.
How much do scores typically increase with ratio curving?
It depends on how far the highest score is below 100%. A top score of 90% raises scores about 11%; a top of 75% raises them about 33%.
What if multiple students score the highest?
The calculator uses the highest score value as the reference. If several students share the top score, they all reach 100% after the curve.
Can I cap the adjustment at a certain number of points?
The standard ratio method scales proportionally without a points cap. If you want a maximum adjustment, use linear instead.
Does ratio curving change student ranking?
No. Every score is scaled by the same multiplier, so relative rankings stay identical.
Still have questions? Get in touch.