Calculated
Weighted Average Calculator
Sign up to favourite this calculatorEnter your values and a matching list of weights. The weighted average appears with the plain average beside it, so you can see what the weighting changed.
Weighted average
Unweighted average
3.325Total weight
13Sum of value × weight
44.6How many pairs
4Weighting effect
+0.1058Save to My calculations
Sign in to keep your calculationsSaved · View in My dashboard
Saving…Saved to My dashboardCouldn't save. We'll try again.That saved calculation isn't available.
Share result
Compare scenarios
Keep this calculation as a scenario, change any input above, and the Now column shows how the result moves. Keep up to three, A to C; Open puts one back in the calculator.
Explain my result
Assumptions and limits
- An estimate from the numbers you entered, for guidance only. It is not financial, tax or medical advice.
- Calculator version 1, last updated 25 October 2026.
Was this calculator useful?
Report a problem
Saved to your account. Go to My dashboard to view your calculations.Link copied. Paste it wherever you want to share it.Your link is ready: open Share result and choose Copy link.
How to use this calculator
- Enter your values in the first box — grades, prices, scores, rates.
- Enter the weights in the second box, in the same order. The third weight belongs to the third value.
- Read the weighted average, then compare it with the unweighted one beside it. The gap between them is what the weighting is doing.
Both boxes take commas, spaces or new lines, so two columns copied out of a spreadsheet can be pasted straight in.
What do I need to enter?
- Values — the figures being averaged, such as grades, scores, prices or rates. Up to 1,000 numbers, separated by commas, spaces or new lines.
- Weights — how much each value counts, in the same order. There must be exactly one weight per value, and the weights must not add up to zero.
What do the results show?
- Weighted average — the sum of each value times its weight, divided by the total weight.
- Unweighted average — the plain mean of the values, for comparison.
- Weighting effect — the weighted average minus the unweighted average, with its sign.
- Total weight, Sum of value × weight and How many pairs — the figures the average is built from.
- Working — the sum written out with your numbers, shortened once the list is long.
How to calculate a weighted average
Each value is counted as many times as its weight says, and the total is divided by the number of counts rather than the number of values.
Weighted mean = Σ(w × x) ÷ Σw
- x — each value, e.g. a grade of 4.0
- w — its weight, e.g. 4 credit hours
- Σ — "the sum of", added across every pair
When every weight is the same, the weights cancel out and the result is the ordinary mean. That is worth knowing: the plain average is just a weighted average where nothing counts for more than anything else.
A worked example: grade point average
| Course | Grade | Credits |
|---|---|---|
| Statistics | 4.0 | 4 |
| Economics | 3.0 | 4 |
| History | 4.0 | 3 |
| Chemistry | 2.3 | 2 |
The products are 4.0 × 4 = 16, 3.0 × 4 = 12,4.0 × 3 = 12 and 2.3 × 2 = 4.6, which add to 44.6. The credits add to 13, so the GPA is 44.6 ÷ 13 = 3.43.
Averaging the four grades without weights gives 3.325. The weighted figure is higher because the weakest grade came from the smallest course — which is exactly the distinction a GPA exists to make.
Frequently asked questions
How do I calculate a weighted average?
Multiply each value by its weight, add those products, then divide by the total weight. For grades 4.0, 3.0, 4.0 and 2.3 with credit weights 4, 4, 3 and 2, the products total 44.6 and the weights total 13, giving 3.43.
How is it different from an ordinary average?
An ordinary average treats every value as equally important. A weighted average lets some count for more. The same four grades average 3.325 unweighted but 3.43 weighted, because the 4.0s carry more credits than the 2.3 does.
What should I use as weights?
Whatever measures how much each value counts: credit hours for a GPA, quantities for an average price, assessment percentages for a course mark, or population sizes when combining regional figures. Weights do not need to add up to 100 or to anything in particular.
Can weights be decimals or percentages?
Yes. Weights of 40, 35 and 25 behave exactly like 0.4, 0.35 and 0.25, because only their relative sizes matter. The division by the total weight cancels any common scale.
Why does it say the lists do not match?
Because there are more values than weights, or the other way round. Each value needs exactly one weight, paired by position, so the first value goes with the first weight. The message shows both counts so you can see which list is short.
Can a weight be zero or negative?
A zero weight is fine — it simply drops that value out of the average. Negative weights are accepted but rarely mean anything; if the weights sum to zero the calculation has no answer, and the calculator says so instead of dividing by zero.
Last updated 25 October 2026.