Weighted Average Calculator: Precision in Your Data

Calculate values where some factors matter more than others.

A simple average treats every number equally. However, in the real world, some numbers carry more importance. Whether you are a student whose final exam is worth 40% of your grade, or an investor buying stocks at different prices.

How It Works: The Formula

On familyhealthcalc.com, we use the standard mathematical approach for weighted means:

• Weighted Average: Σ (w_i × x_i) Σ w_i

• w: The weight assigned to the value.
• x: The value itself.
• ∑: The sum of all calculated products divided by the sum of all weights.

Example: Grading

If your Homework is 20% of your grade (Score: 90) and your Final Exam is 80% (Score: 70):

• (90 × 0.20) = 18
• (70 × 0.80) = 56
• Weighted Average: 18 + 56 = 74
• (A simple average would have incorrectly suggested 80)

Practical Applications

• Academic Grading: Perfect for “Grade Weighting” where the final exam, midterms, and participation all have different impacts on your GPA.
• Investment Portfolios: Calculate the Weighted Average Cost of Capital (WACC) or the average purchase price of a stock bought at different intervals (Dollar Cost Averaging).
• Business Inventory: Use it for the Weighted Average Cost method to determine the value of inventory when items are purchased at varying costs over time.
• Product Reviews: Businesses can weight recent reviews more heavily than older ones to get a more accurate “Current” satisfaction score.