Weighted Average Calculator
Enter one value and weight per line and get the weighted average, with a table showing each row's share of the total weight and what it adds to the result. Weights can be percentages, credit hours or points. A second panel works out the average you need on the work still to come to reach the target you want. Everything runs in your browser.
Weights can be percentages, credit hours or points. They are scaled by their total, so they do not need to add up to 100.
| Value | Weight | Share | Adds |
|---|---|---|---|
| 92 | 15 | 20% | 18.4 |
| 85 | 25 | 33.3333% | 28.3333 |
| 78 | 20 | 26.6667% | 20.8 |
| 88 | 15 | 20% | 17.6 |
| Total | 75 | 100% | 85.1333 |
Each row adds its value times its share of the total weight. The weighted average is the sum of the last column.
You need an average of 104.6 on the remaining work. That is above 100, so this target cannot be reached with a top score of 100.With a score of 100 on the rest, you would finish on 88.85. With 0, you would finish on 63.85.
A weighted average counts each value in proportion to its weight: multiply every value by its weight, add the results, and divide by the total weight. A final exam worth 40 percent moves your grade four times as much as a quiz worth 10 percent. The same method gives a GPA, where the weights are credit hours. Everything is worked out in your browser and nothing is uploaded.
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Math & MoneyAbout the Weighted Average Calculator
A weighted average gives each value a different importance. Multiply each value by its weight, add the products, and divide by the total weight. With a 90 worth 30 percent, an 80 worth 20 percent and a 70 worth 50 percent, the weighted average is (90 x 30 + 80 x 20 + 70 x 50) divided by 100, which is 78. The plain average of the same three numbers is 80, so the heavy 70 pulls the weighted result down. Weights do not need to add up to 100: they are scaled by their total, so weights of 3, 2 and 5 give the same answer as 30, 20 and 50, and credit hours work the same way for a grade point average. A weight of 0 is allowed and simply ignores that value. The second panel solves the usual question of what you need on the remaining work. If your work so far averages 85 across 75 percent of the grade and the final exam is the other 25 percent, a target of 80 needs 65 on the final, while a target of 90 needs 105, which is impossible with a top score of 100. The panel says so and shows the best and worst final averages you could still finish with. Weighted averages also appear in portfolio returns, price indexes and survey results where groups have different sizes.
How do you calculate a weighted average?▾
Multiply each value by its weight, add up the results, and divide by the sum of the weights. For 90 at 30 percent, 80 at 20 percent and 70 at 50 percent, the answer is 7800 divided by 100, which is 78.
Do the weights have to add up to 100?▾
No. The weights are divided by their total, so any positive numbers work. Weights of 3, 2 and 5 give the same result as 30, 20 and 50. Credit hours and points work the same way.
How do I find the grade I need on a final exam?▾
Multiply your target by the total weight, subtract the points you already have, and divide by the weight of the exam. With an 85 average on 75 percent and a final worth 25 percent, reaching 80 needs 65 on the final.
What is the difference between a weighted average and a simple average?▾
A simple average treats every value equally. A weighted average lets some values count more, so a large exam can matter more than a small quiz.
Is my data uploaded?▾
No. The calculation runs in your browser and nothing you enter is sent anywhere.