Education
How to Calculate Grades and GPA
Convert scores to percentages, calculate weighted grades, and understand GPA calculations.
- 5 min read
Formula
Percentage = (Points Earned ÷ Total Points) × 100
Try it yourself
Converting Scores to Percentages
The basic formula for converting any score to a percentage:
Example:
You scored 85 out of 100 on a test:
Percentage = (85 ÷ 100) × 100 = 85%
Standard Grade Scale
| Letter Grade | Percentage | GPA Points |
|---|---|---|
| A+ | 97-100% | 4.0 |
| A | 93-96% | 4.0 |
| A- | 90-92% | 3.7 |
| B+ | 87-89% | 3.3 |
| B | 83-86% | 3.0 |
| B- | 80-82% | 2.7 |
| C+ | 77-79% | 2.3 |
| C | 73-76% | 2.0 |
| C- | 70-72% | 1.7 |
| D | 60-69% | 1.0 |
| F | Below 60% | 0.0 |
Weighted Grades
When assignments have different weights:
Example:
- Homework (20%): 95%
- Midterm (30%): 85%
- Final (50%): 90%
Weighted Grade = (95×0.20 + 85×0.30 + 90×0.50) = 19 + 25.5 + 45 = 89.5%
Calculating GPA
Example:
| Course | Credits | Grade | Points |
|---|---|---|---|
| Math | 4 | A (4.0) | 16 |
| English | 3 | B+ (3.3) | 9.9 |
| Science | 4 | A- (3.7) | 14.8 |
| History | 3 | B (3.0) | 9 |
| Total | 49.7 | ||
GPA = 49.7 ÷ 14 = 3.55
What Grade Do I Need?
To calculate the grade needed on a final exam:
Example:
Current grade: 85%, Final is 30% of grade, Target: 90%
Needed = (90 - 85 × 0.70) ÷ 0.30 = (90 - 59.5) ÷ 0.30 = 101.7%
You would need over 100% on the final - might need to adjust your target!
Frequently Asked Questions
How do I convert a test score to a percentage?
Divide the points earned by the points possible and multiply by 100: 42 out of 50 is 42 ÷ 50 × 100 = 84%.
How is a weighted grade calculated?
Multiply each score by its weight, add the results and divide by the total weight. Homework at 90% with a 30% weight plus an exam at 80% with a 70% weight gives 90 × 0.3 + 80 × 0.7 = 83%.
What grade do I need on the final exam?
Needed = (target − current grade × (1 − final weight)) ÷ final weight. With a 78 average, a final worth 40% and a target of 80, you need (80 − 78 × 0.6) ÷ 0.4 = 83%.