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Weighted Average Calculator

Calculate a weighted average from values that do not all count equally. Enter each value with its weight, switch between percent and raw relative weights, and see the normalized share behind the final answer.

Examples

Assignment categories

Combine test, project, and homework scores without pretending they count equally.

Weight format
percent
Rows
92|40 84|35 78|25
Weighted average
85.7
Total entered weight
100 %
Normalization
Weights already total 100%, so each normalized share matches the entered percent.
Contribution breakdown
Row 1: value 92 × share 40.00% = 36.8000, Row 2: value 84 × share 35.00% = 29.4000, Row 3: value 78 × share 25.00% = 19.5000

Examples

Assignment categoriesCombine test, project, and homework scores without pretending they count equally.85.7
Review average by response countWeight each source rating by how many reviews it represents.4.6341
KPI scorecardMix on-time delivery, margin, and quality into one weighted score.85.3

How It Works

Formula

Weighted average=∑(vi×wi)∑wi\text{Weighted average} = \frac{\sum (v_i \times w_i)}{\sum w_i}

Normalized sharei=wi∑wi\text{Normalized share}_i = \frac{w_i}{\sum w_i}

Contributioni=vi×Normalized sharei\text{Contribution}_i = v_i \times \text{Normalized share}_i

Variables

viv_i

Value in row i

wiw_i

Positive weight in row i

∑wi\sum w_i

Total entered weight

Enter one row per component with a value and a positive weight. The calculator multiplies every value by its weight, adds those products, and divides by the total entered weight. That is why a weighted average can differ from a regular average even when the same values are involved.

Frequently Asked Questions

01How is a weighted average different from a regular average?
A regular average gives every value the same influence. A weighted average multiplies each value by its weight first, so larger weights count more in the final result.
02Do my weights have to add up to 100%?
No. This calculator divides by the total entered weight, so percent weights that total 80% or raw weights like 5, 3, and 2 still produce the correct weighted mean.
03Can I use negative values?
Yes. Negative values are allowed when they represent a real signed quantity. Weights still need to stay positive so the weighting itself remains meaningful.
04Does this know my grading or business rules?
No. It only applies the weighted-mean arithmetic. It does not know GPA policy, dropped categories, tax logic, KPI caps, or any institution-specific interpretation.

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