Weighted Average Calculator: Easily Compute Relevance-Based Averages

How to use the tool

1. Enter a value in “Value 1” (e.g., 60 or 150).
2. Assign its weight % in “Weight 1” (e.g., 40 % or 25 %).
3. Click “Add Input” to create “Value 2 / Weight 2” and so on—no hard limit.
4. Repeat until every important figure and its weight are listed.
5. Ensure the weights total 100 %; the result box turns red if they do not.
6. Press “Calculate”; the JavaScript returns your weighted average instantly.

Formula used

For n pairs, the calculator applies:

$$ \text{Weighted Average}=rac{\sum_{i=1}^{n}(w_i \times v_i)}{100} $$

Example calculation 1

• Value 1 = 60, Weight 1 = 40 %
• Value 2 = 95, Weight 2 = 60 %
• Weighted Average = 0.40 × 60 + 0.60 × 95 = 24 + 57 = 81

Example calculation 2

• Value 1 = 200, Weight 1 = 20 %
• Value 2 = 50, Weight 2 = 80 %
• Weighted Average = 0.20 × 200 + 0.80 × 50 = 40 + 40 = 80

Quick-Facts

• Valid weight range: 0–100 % per input (HTML Standard, 2023).
• All weights must sum to 100 % for a proper average (Statistics Explained, 2022).
• GPA systems weight courses by credits (U.S. Dept of Education, https://www2.ed.gov/).
• Portfolio models constrain weight totals to 100 % of capital (CFA Institute, 2020).

FAQ

What distinguishes a weighted from a simple average?

A simple average gives every value equal influence, while a weighted average scales influence by assigned percentages (Investopedia, 2023).

How does the calculator verify my weights?

It sums all percentages on each keystroke and flags an error if the total deviates from 100 % by more than 0.01 % (HTML Standard, 2023).

Can weights exceed 100 %?

No. Exceeding 100 % distorts proportionality and breaches accounting conservation rules (CFA Institute, 2020).

Which fields commonly rely on weighted averages?

Finance, education, environmental science and project management all depend on weighted averages for composite metrics (OECD Data, 2022).

Why force the total weight to equal 100 %?

Using 100 % keeps the final average on the same scale as the input values, ensuring interpretability (Statistics Explained, 2022).

How many pairs can I add?

The script dynamically appends input blocks; browser performance, not code, sets the practical limit—thousands are possible on modern devices (MDN Web Docs, 2023).

Are negative values allowed?

Yes. Negative numbers represent deficits or losses and calculate correctly as long as weights remain positive (AccountingTools, 2021).

How do I keep my data for later sessions?

The tool stores inputs in localStorage; reopening the page restores them until you clear your browser cache (MDN Web Docs, 2023).