Calculate a curved test or exam grade by adding curve points or adjusting scores based on the highest score in the class.
Grading scales can vary by school, teacher or course. This calculator uses a common U.S. letter-grade scale.
A grade curve is a method used to adjust test, exam or assignment scores after they have been graded. Instead of using the original percentages without changes, an instructor may increase scores to account for the difficulty of an assessment or the overall performance of the class.
There are several ways to curve grades. A simple method is to add the same number of percentage points to every score. Another common approach is to adjust the highest score in the class to 100% and increase the remaining scores by the same amount.
This grade curve calculator supports both methods and shows the adjusted percentage together with an estimated letter grade.
Use the calculator to estimate your curved grade in a few simple steps.
If your instructor uses a different grading or curving method, your actual result may be different from the estimate shown here.
Grade curving changes the original score according to a rule selected by the instructor. The goal is often to compensate for a difficult test or to adjust results when the entire class scored lower than expected.
For example, if the highest score on an exam is 94%, an instructor could add 6 percentage points to every student’s score so that the highest result becomes 100%. A student who originally earned 78% would then receive an adjusted score of 84%.
Another method is to choose a fixed adjustment, such as adding 5 points to every score. The same curve is then applied consistently to each student.
When the highest score in the class is adjusted to 100%, first calculate the number of curve points:
Then add those points to the original score:
For a fixed-point curve, the calculation is even simpler:
The calculator limits the final result to 100%.
Suppose you earned 76% on a test and the highest score in the class was 92%.
Step 1: 100 − 92 = 8 curve points
Step 2: 76 + 8 = 84%
Curved grade: 84%
Estimated letter grade: B
If the instructor applies the same curve to everyone, each student receives an 8-point increase while the highest score becomes 100%.
There is no single universal way to curve grades. Instructors may use different methods depending on the difficulty of the test, the distribution of scores and the grading policy of the course.
The calculator above supports the first two methods because they are simple, transparent and easy to apply consistently.
A grade curve is a broad term for any method that adjusts grades after an assessment. A bell curve is a more specific approach based on the distribution of student performance across a class.
With a statistical bell curve, grades may be assigned according to how far each score falls above or below the class average. This can produce a distribution where fewer students receive the highest and lowest grades and more students fall near the middle.
In everyday classroom use, the term “bell curve” is sometimes used more loosely for any score adjustment. This calculator does not apply a full statistical normal-distribution model; it uses straightforward point-based adjustments.
After a score is curved, the calculator converts the adjusted percentage into a letter grade using the following common U.S. grading scale.
| Letter Grade | Percentage Range |
|---|---|
| A+ | 97–100% |
| A | 93–96.99% |
| A− | 90–92.99% |
| B+ | 87–89.99% |
| B | 83–86.99% |
| B− | 80–82.99% |
| C+ | 77–79.99% |
| C | 73–76.99% |
| C− | 70–72.99% |
| D+ | 67–69.99% |
| D | 63–66.99% |
| D− | 60–62.99% |
| F | Below 60% |
Schools and instructors may use different cutoffs, so always compare the result with the grading scale used in your course.
One simple method is to subtract the highest score from 100 and add the difference to each student’s original score. For example, if the highest score is 92%, the curve adds 8 percentage points.
Curving a grade means adjusting the original score or grading scale after an assessment. The adjustment may raise scores, change letter-grade boundaries or compare results with the overall class performance.
Some instructors may allow scores above 100%, but this calculator caps the adjusted result at 100% for a simple percentage-based grade.
Not necessarily. Grade curve is a general term for adjusting grades, while a bell curve usually refers to assigning grades based on the statistical distribution of scores across a class.
No. Curving methods vary by teacher, school and course. Some instructors add points, some adjust grade cutoffs, and others use statistical methods.