What is a Curved Test Grade?
Sometimes a test is so difficult that the entire class performs poorly. In these cases, teachers may "curve" the grades to adjust the distribution. Here are the three most common methods used:
[Image of bell curve grading distribution]1
The Flat Curve
The teacher adds the same number of points to everyone's score.
Example
Raw: 70%
+ 10 Points
New: 80%
2
The 100% Scale
The highest score in the class becomes 100%. The difference is added to everyone.
Example
Top Score: 88%
Gap: 12 pts
Everyone +12
3
Square Root Curve
Helps lower grades more than higher grades. Formula: √Score × 10.
Example
Raw: 64%
√64 = 8
8 × 10 = 80%
The Basic Formula
Calculating a test score involves a simple percentage formula. You are essentially finding out what "portion" of the test you got right compared to the whole.
Score = (Correct ÷ Total) × 100Or if counting wrong answers:
Score = ((Total - Wrong) ÷ Total) × 100Real World Example
50
Total Questions
5
Wrong Answers
Final Score:
90%(45 Correct)
Test Grading FAQ
Common questions about calculating test scores and understanding grading scales.
How do I calculate my test grade if it's out of points?
Divide your points earned by the total points possible, then multiply by 100. For example, if you got 45 points out of 60: (45 ÷ 60) × 100 = 75%.
What is a Square Root Curve?
A square root curve helps students with lower grades significantly. The formula is: Square Root of Raw Score multiplied by 10. Example: A raw 64% becomes an 80% (√64 = 8, 8x10 = 80).
If I got 17 out of 20, what is my grade?
17 divided by 20 is 0.85. Multiply by 100 to get 85%. This is typically a 'B' grade.
How much does one test affect my overall grade?
It depends on the weight of the test category in your syllabus. If 'Tests' are worth 50% of your grade and you take 5 tests, each single test is worth 10% of your final grade.
Do teachers round up test grades?
It depends on the teacher's policy. Many teachers round a 0.5 or higher up to the next whole number (e.g., 89.5 becomes 90), but this is not a universal rule.