Weighted Average Calculator Formula
Understand the math behind the weighted average calculator. Each variable explained with a worked example.
Formulas Used
Weighted Average
weighted_avg = weighted_sum / (total_weight / 100)Total Weight
weight_check = total_weightShould equal 100%
Simple Average (comparison)
simple_avg = (score1 + score2 + score3 + score4) / 4Variables
| Variable | Description | Default |
|---|---|---|
score1 | Category 1 Score(%) | 90 |
weight1 | Category 1 Weight(%) | 20 |
score2 | Category 2 Score(%) | 85 |
weight2 | Category 2 Weight(%) | 30 |
score3 | Category 3 Score(%) | 78 |
weight3 | Category 3 Weight(%) | 30 |
score4 | Category 4 Score(%) | 95 |
weight4 | Category 4 Weight(%) | 20 |
total_weight | Derived value= weight1 + weight2 + weight3 + weight4 | calculated |
weighted_sum | Derived value= score1 * weight1 / 100 + score2 * weight2 / 100 + score3 * weight3 / 100 + score4 * weight4 / 100 | calculated |
How It Works
How to Calculate a Weighted Average
Formula
Weighted Average = Sum of (Score x Weight) / Sum of Weights
Weights should add up to 100%. Higher-weighted categories have more impact on your final grade.
Worked Example
Homework (90%, 20%), Midterms (85%, 30%), Final (78%, 30%), Participation (95%, 20%).
score1 = 90weight1 = 20score2 = 85weight2 = 30score3 = 78weight3 = 30score4 = 95weight4 = 20
- 01Homework: 90 x 0.20 = 18.0
- 02Midterms: 85 x 0.30 = 25.5
- 03Final: 78 x 0.30 = 23.4
- 04Participation: 95 x 0.20 = 19.0
- 05Total: 85.9 / 1.00 = 85.9%
Frequently Asked Questions
What if weights do not add to 100%?
The calculator normalizes by dividing by the actual total weight. Check your syllabus to confirm weights.
Why is weighted average different from simple average?
Weighted average gives more influence to higher-weighted categories.
How do I find my assignment weights?
Check your course syllabus for grade categories and their percentage weights.
Ready to run the numbers?
Open Weighted Average Calculator