# Weighted average calculator

> A weighted average multiplies each score by the matching weight, adds the products, and divides by the sum of the weights. If exams count 40% with an 88, homework counts 20% with a 94, and a project counts 40% with a 76, the course grade is (3,520 + 1,880 + 3,040) ÷ 100 = 84.4. Another tab finds the score needed on the final exam.

Source: https://www.calterix.com/en-us/calculator/average/weighted-average/ · Updated 11/06/2026 · en-US

## How to calculate a weighted average

Each score counts as much as its weight. A final exam weighted at 5 counts five times as much as a quiz weighted at 1. Dividing by the sum of the weights keeps the result on the same scale as the scores.

```
Average = (s₁·w₁ + s₂·w₂ + … + sₖ·wₖ) ÷ (w₁ + w₂ + … + wₖ)
Score needed = (grade you want × total of all weights − Σ scores·weights) ÷ weight of the final
```

This page is the grade-focused version of the [average calculator](https://www.calterix.com/en-us/calculator/average/), which also covers the mean, median, mode, geometric mean, and harmonic mean. To turn letter grades into a 4.0 GPA, use the [GPA calculator](https://www.calterix.com/en-us/calculator/gpa/).

## Worked examples

| Scores | Weights | Math | Average |
| --- | --- | --- | --- |
| 88, 94, 76 | 40, 20, 40 | (3,520 + 1,880 + 3,040) ÷ 100 | 84.4 |
| 5, 10 | 1, 1 | 15 ÷ 2 | 7.5 |
| 7, 4 | 3, 1 | (21 + 4) ÷ 4 | 6.25 |
| 84, 95 | 40, 20 | 5,260 ÷ 60 | 87.6667 |

Answers checked by hand.

Score needed on the final: you have an 84 on exams (40%) and a 95 on homework (20%), and the final is worth 40%. To finish with a 90, you need (90 × 100 − 5,260) ÷ 40 = 93.5. For an 80 in the course, the math gives (8,000 − 5,260) ÷ 40 = 68.5.

## Common mistakes

- Using a plain average when the syllabus sets weights. The two match only when all weights are equal.
- Entering weights as percents is fine: 20, 30, 50 is the same as 2, 3, 5.
- Forgetting that the score you need can pass 100. When it does, the target is out of reach without extra credit.
- Rounding too early. Keep every decimal until the end, then round the way your instructor does.

> Rounding rules, extra credit, dropped scores, and passing cutoffs differ by school and instructor. Check the syllabus or the school handbook.

To see how much the scores vary around the average, use the [standard deviation calculator](https://www.calterix.com/en-us/calculator/standard-deviation/).

## Frequently asked questions

### How do you calculate a weighted average for grades?

Multiply each score by its weight, add the products, and divide by the sum of the weights. With scores 88, 94, and 76 and weights 40, 20, and 40, the result is 8,440 ÷ 100 = 84.4.

### How do I calculate what I need on the final exam?

Use (grade you want × total weight − points earned so far) ÷ weight of the final. With 5,260 points so far and a final worth 40%, a 90 in the course takes (9,000 − 5,260) ÷ 40 = 93.5.

### Can I use percents as weights?

Yes. Weights of 20, 30, and 50 give the same result as 2, 3, and 5, because dividing by the sum of the weights cancels the scale.

### What if the score I need on the final is over 100?

The grade you want can't be reached with a top score on the final. The calculator flags any result above the highest possible score. Ask your instructor about extra credit or other ways to make up points.

### What is the difference between a weighted average and a regular average?

In a regular average, every score counts the same. In a weighted average, each score has its own weight. The two match only when all weights are equal.

### How do I find my class grade when exams are 40% and homework is 20%?

Multiply the exam average by 0.40 and the homework average by 0.20, then add the other categories the same way. With an 88 on exams and a 94 on homework, those two pieces give 35.2 + 18.8 = 54 points toward the course grade.