Statistics & Data Analysis

Weighted Average Calculator

Calculate the weighted average of a dataset where each value has a different importance (weight). Perfect for GPA calculation, investment portfolios, and survey analysis.

Weighted Average Concept

Weight 1Weight 2Weight 3Weight 4Weight 5Weighted Average

Enter Values and Weights

ValueWeightWeightedAction
255.00
368.00
156.00
270.00
Pro Tip

Weights don't need to sum to 1 or 100 – the calculator normalizes them automatically.

Weighted Average Results

Weighted Average

87.4167

Total Weight

12.00

Weighted Sum

1049.00

Governing Formula

Weighted Average = Σ(Value × Weight) / Σ Weights
Σ—

Sum of weighted values

Σ Weights—

Total weight

Engineering Code

Python
def weighted_average(data):
    # data: list of dicts with 'value' and 'weight'
    total_weight = sum(item['weight'] for item in data)
    weighted_sum = sum(item['value'] * item['weight'] for item in data)
    return weighted_sum / total_weight

data = [
    {'value': 85, 'weight': 3},
    {'value': 92, 'weight': 4},
    {'value': 78, 'weight': 2},
    {'value': 90, 'weight': 3},
]
result = weighted_average(data)
print(f"Weighted Average: {result:.2f}")

Technical Explanation: Weighted Average

A weighted average assigns different levels of importance (weights) to each data point, reflecting its contribution to the overall average. It is widely used in finance (portfolio returns), education (GPA), and statistics (survey analysis).

Weighted Average = Σ (Value × Weight) / Σ Weights

Key Concepts

  • Value: The numerical data point (e.g., grade, price, return).
  • Weight: The importance or frequency of the value (e.g., credit hours, market cap, number of respondents).
  • Weighted Average: The result that gives more influence to higher‑weighted items.

How to Use the Calculator

  1. Enter each Value and its corresponding Weight.
  2. Add as many rows as needed.
  3. The calculator instantly shows the weighted average, total weight, sum of weighted values, and a summary.

Real-World Engineering Cases

Grade Point Average (GPA)

A student has grades: A (4.0) in 3‑credit course, B (3.0) in 4‑credit course, and A- (3.7) in 2‑credit course. Weighted average = (4.0×3 + 3.0×4 + 3.7×2) / (3+4+2) = (12+12+7.4)/9 = 31.4/9 = 3.49 GPA.

Engineering Lesson

Weighted average accounts for course credit hours, giving a more accurate measure of academic performance.

Investment Portfolio Return

An investor has 40% of portfolio in stocks (return 12%), 30% in bonds (return 5%), 20% in real estate (return 8%), and 10% in cash (return 1%). Weighted average return = (0.4×12 + 0.3×5 + 0.2×8 + 0.1×1) = 4.8+1.5+1.6+0.1 = 8.0%.

Engineering Lesson

Portfolio returns are always weighted by allocation to reflect the true blended performance.

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Frequently Asked Questions

When should I use a weighted average instead of a simple average?

Use weighted average when data points have different levels of importance (e.g., grades with different credit hours, portfolio allocations, survey responses with different respondent counts).

Can weights be percentages?

Yes, weights can be expressed as percentages (summing to 100%) or as any numbers (e.g., credit hours, counts). The calculator handles both.

What if my weights don't sum to 1 (or 100%)?

The calculator automatically normalizes weights by dividing by the total weight, so the sum doesn't have to equal 1 or 100.