Grade Curve Calculator
“The exam will be curved” can mean three different things. This calculator applies the three classic curves — square-root, flat points added, and scaling so the top score becomes 100 — and shows the curved score with its letter grade before and after.
Results
Formula
How to use this calculator
- Choose the curve type your teacher announced.
- Enter your original score (and the extra input that curve needs).
- Press Calculate for the curved score and letter change.
Worked example
A score of 64% under a square-root curve.
- √64 = 8.
- Curved: 10 × 8 = 80%.
Result: 64% curves to 80% — from an F to a B− on the standard scale used here.
Frequently asked questions
Which curve is most common?
The square-root curve is a classroom favorite because it is one formula, needs no class data, and compresses the top less than the bottom. Scaling to the highest is also common after a hard exam.
Can a curve ever lower my grade?
Standard curves only raise scores. A true “bell curve” re-normalizes everyone to a distribution, which can lower some grades — none of the three methods here do that.
Does the curved score change my letter grade automatically?
Only if it crosses a boundary on your school’s scale. The scale used here is the common 90/80/70/65 ladder; your syllabus controls the real boundaries.
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