Weighted Average Calculator

How to calculate a weighted average

1. Enter a value and its corresponding weight in each row. Keep the values on the same unit and scale, and use one basis for all weights.
2. Add or remove rows as needed. A fully blank row is ignored; a partly completed row must be finished or cleared.
3. Check the weighted average, rows with positive weight and total weight. At least one weight must be positive.
4. Open Calculation details for the exact weighted sum and method. Copy the qualified summary or clear the entries when finished.

A focused weighted-mean calculation

• Enter up to 50 value–weight pairs without account creation or file upload.
• Use positive, negative or zero values with nonnegative weights.
• Enter decimal points or commas in separate numeric fields, without a format selector.
• Check the total weight and exact sum of value × weight.
• Keep rounded, tiny and zero results clearly distinguished on screen and in the copied summary.

When values have different contributions

• Combine numeric scores already on the same scale using their known relative weights, without converting letter grades or assuming a course policy.
• Combine comparable group means using each group's relevant observation count as its weight.
• Find a quantity-weighted mean of comparable per-unit measurements when the quantities use one consistent unit.

Understanding values, weights and the result

Multiply each value by its weight, add the products, then divide by the sum of weights. For values 12 and 24 with weights 1 and 2, the weighted sum is 60, the total weight is 3 and the weighted average is 20.

Weights describe relative contributions, not necessarily percentages. The weights 2 and 3, 40 and 60, and 0.4 and 0.6 give the same proportions. Do not mix percentage-style numbers with decimal proportions in the same set.

A zero-weight row contributes nothing, but still needs a valid value. A blank value is not zero and a missing weight is not one. If every weight is zero, there is no weighted average to display.

A point or comma is always a decimal mark in a field. Both 1.000 and 1,000 mean one, not one thousand. Enter one thousand as 1000. Digit grouping, percentage signs, units, fractions and exponent notation are not accepted.

For included course assessments, the result is the average of those included scores and weights, not a forecast of a final grade. Keep score scales comparable. To combine group averages, use suitable group counts; averaging group totals is a different calculation.

Weighted average examples

Values 12 and 24 with weights 1 and 2 give (12 × 1 + 24 × 2) ÷ 3 = 20.

Scores 72 and 92 with relative weights 25 and 75 give 87. Using 1 and 3 instead gives the same answer.

Group means of 30 and 50 for groups of 8 and 12 comparable observations combine to 42, not the unweighted mean of 40.

Values −6 and 9 with weights 2 and 1 give −1. Negative values are allowed; negative weights are outside this tool's scope.

Values 1 and 2 with weights 1 and 2 give 5 ÷ 3. The displayed mean is About 1.666667 because only the final mean is rounded.

What the calculator does not decide

Use 1–50 rows, at most 32 raw characters per field and up to four decimal places. Values must be between −1 billion and 1 billion; weights must be between zero and 1 billion, with at least one positive weight.

Weights need not total 100, but their meaning and basis must be consistent. This tool does not choose suitable statistical weights, convert letter grades, determine GPA rules, forecast final grades or provide financial advice.

A weighted mean is not automatically representative or more accurate than another average. The values must be comparable and the chosen weights appropriate. A nonzero result smaller in magnitude than 0.000001 is shown as a signed interval instead of false zero.

Your entries and copied result

The calculator keeps its entries in page memory without an account, upload, saved history or input-bearing share link. Copy is optional and copies a qualified summary, not the complete list.

The surrounding website can make ordinary requests under its existing consent and analytics settings. Local calculation is not whole-site privacy certification.