How to use it
- On each line of Values and weights, type a value and its weight, for example 85 4 for a grade of 85 with 4 credits.
- Put a semicolon between them if you prefer, for example 78; 3. Blank lines are ignored.
- Read the Weighted average and the Total weight as you type.
- Check Each value and its weight and How it is worked out to see how each product was added.
The formula
A weighted average gives each value a share of the result in proportion to its weight. You multiply each value by its weight, add the products, and divide by the sum of the weights. When every weight is 1, this is the ordinary average.
If the weights are not shares that add up to 1, the division by the total weight is what makes the result a true average. The result always lies between the smallest and the largest value.
weighted average = Σ(value × weight) ÷ Σ(weight)Grades weighted by credits
A course with 4 credits should count more in your grade point average than one with 1 credit. Enter each course grade as the value and its credits as the weight. The result is the average grade per credit, a common way of weighting a term or a degree average.
Check the rules of your own school or university: some use a grade-point scale instead of percentages, and some exclude failed courses or courses taken to repeat a grade. This calculator works with the numbers you enter; it does not know those rules.
Prices weighted by quantity
To find the average price you paid for a product bought at several prices, enter each unit price as the value and the quantity bought at that price as the weight. The result is the average price per unit, not the simple average of the prices, which would give the same weight to a small and a large purchase.
Worked example: four courses
Grades 85 (4 credits), 78 (3 credits), 91 (3 credits) and 88 (2 credits). Each grade times its credits gives 340, 234, 273 and 176: a sum of 1,023 over 12 credits.
The weighted average is 1,023 ÷ 12 = 85.25. The simple average of the four grades would be 85.5, a little higher, because the 88 in the 2-credit course counts for less when the credits are used as weights.
| Value | Weight | Value × weight |
|---|---|---|
| 85 | 4 | 340 |
| 78 | 3 | 234 |
| 91 | 3 | 273 |
| 88 | 2 | 176 |
| Total | 12 | 1,023 |
Frequently asked questions
What is the difference between a weighted and a simple average?
A simple average gives every value the same weight. A weighted average gives each value a share in proportion to its weight, such as credits or quantity, so larger weights pull the result towards their values.
Can I use decimal numbers or percentages?
Yes. Write decimals with a point, such as 85.5 4, and write a percentage as its number, for example 85 for 85%. The average is then a percentage too.
Why do I get an error for one line?
The message gives the line number. Each line needs exactly two numbers, a value and a weight, separated by a space or a semicolon. A weight cannot be negative, and at least one weight must be above 0.
Can a weight be 0?
Yes. A row with weight 0 is listed in the table but does not change the average. If every weight is 0, there is no average, and the calculator says so.
Are the numbers I enter sent to a server?
No. The calculation runs in your browser, and nothing you enter is sent to us.
Sources
Figures and text last checked on Tuesday, November 10, 2026.