Weighted Score Calculator
Combine up to four scores with different weights into a single weighted average — the math behind grades, ratings and indexes.
How it works
Weighted score = Σ(scoreᵢ × weightᵢ) ÷ Σ(weightᵢ)
A weighted average lets some scores count more than others. Each score is multiplied by its weight, the products are summed, and the total is divided by the sum of the weights — which normalizes the result even if the weights do not add up to exactly 100%. When every weight is equal, the weighted average collapses back to the ordinary mean.
Worked example
Scores of 90, 80 and 70 weighted 40%, 30% and 30%: (90×40 + 80×30 + 70×30) ÷ 100 = (3600 + 2400 + 2100) ÷ 100 = 81. The plain average of the three would be 80, so the heavier weight on the 90 nudges it up to 81.
Sources: Weighted arithmetic mean — Wikipedia
Frequently asked questions
Do the weights have to add up to 100%?
No. The formula divides by the sum of the weights, so any set of positive weights works — 2, 3 and 5 give the same result as 20%, 30% and 50%. The tool flags when the total is not 100% for clarity.
How is this different from a plain average?
A plain average treats every value equally. A weighted average lets more important scores pull the result harder, which is why final grades, review ratings and stock indexes are almost always weighted.
What if I only have two or three scores?
Leave the unused weight at 0 and it is ignored entirely. Only components with a positive weight affect the result.
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This calculator is for educational purposes. Double-check important results before acting on them.