Find out what your grade becomes after a curve, or curve a whole class in one go. Choose from the five curves teachers use most and see the math for every score.
Choose a curve method, fill in the numbers and press Curve it. The curved score and the math appear here.
How to use the grade curve calculator
- Choose My score to see your own curved grade, or My class to curve every score at once.
- Pick the curve method your teacher uses. If you are not sure, ask, because each method gives a different result.
- Fill in the numbers. Students need their score and what the teacher shared, such as the highest score or the class average. Teachers paste the whole list of scores.
- Press Curve it. Teachers can copy the curved scores straight back into a gradebook, in the same order, or print them.
The five common ways to curve grades
1. Highest score becomes 100
Find the gap between the top score and 100, then add that gap to every score. If the highest score is 92%, everyone gets 8 more points, so a 70 becomes a 78. Every student gains the same amount.
2. Add points
The teacher adds a fixed number of points to everyone, for example 5 points to every score. It is the simplest curve and is often used when one question was unfair.
3. Scale to the highest score
Curved score = score × 100 ÷ highest scoreWith a top score of 92%, a 70 becomes 70 × 100 ÷ 92 = 76.09. Everyone is multiplied by the same number, so higher scores gain slightly more points than lower ones.
4. Square root curve
Curved score = 10 × √scoreA 70 becomes 10 × √70 = 83.67, and a 49 becomes 70. Low scores rise the most, while a perfect 100 stays at 100. Teachers use it when a test was hard for most of the class.
5. Target average (bell curve)
The teacher picks the average they want, for example 78%, and moves every score by the same amount so the class average lands there. If the class averaged 72%, everyone gains 6 points.
A full bell curve also changes the spread of scores, measured by the standard deviation. Scores are pulled closer together or pushed further apart around the new average. In the calculator, add a target spread to do this, or leave it blank to only shift scores.
The same scores, five curves
A class where the highest score is 92%. The target average curve depends on the whole class, so it is not shown here.
| Original | Highest to 100 | Add 5 | Scale | Square root |
|---|---|---|---|---|
| 92% | 100% | 97% | 100% | 95.92% |
| 85% | 93% | 90% | 92.39% | 92.2% |
| 70% | 78% | 75% | 76.09% | 83.67% |
| 55% | 63% | 60% | 59.78% | 74.16% |
Which curve is fairest?
There is no single correct answer, and each teacher chooses. As a rough guide:
- Highest score to 100 and add points treat every student the same and are easy to explain.
- Scale keeps the gaps between students in proportion.
- Square root helps struggling students most and changes top scores the least.
- Target average controls the class average directly, but it can lower scores if the class did well. That is why the calculator never lowers a score unless you turn that setting off.
Frequently asked questions
How do I find out how my teacher curves?
Ask your teacher or check the syllabus. Teachers usually say which method they use, or at least share the highest score or the class average.
Can a curve lower my grade?
The first four methods only add points. A target average curve can lower scores when the class average is already above the target, so many teachers keep the original score in that case. The calculator does the same unless you turn off “Never lower a score”.
Is a bell curve the same as curving grades?
Not quite. “Curving” means any adjustment, like adding points. A bell curve is one specific method that sets the class average and spread, and some versions also assign letter grades by rank.
What if a curved score goes over 100?
By default it is capped at 100%. Turn off “Cap scores at 100%” if your teacher allows scores above 100.
Can I paste scores from a spreadsheet?
Yes. Copy a column of scores from Excel or Google Sheets and paste it into the box. The curved scores come back in the same order, so you can paste them next to the originals.
Are the scores saved anywhere?
No. Everything runs in your browser and nothing you type is sent to our server.