HIFreeTools
ENES

Weighted Average Calculator

Calculate a weighted average from a list of values and their weights — add or remove rows freely. Ideal for grades, prices, and survey scores.

Weighted average
83
Σ (value × weight)
83
Σ weight
1
Rows used
3

Weighted average = Σ(value × weight) ÷ Σ(weight). Rows missing a value or weight are ignored.

Quick answer

A weighted average multiplies each value by its weight, adds those products, and divides by the total of the weights: Σ(value × weight) ÷ Σ(weight). For values 90, 80, 70 with weights 0.5, 0.3, 0.2, the result is (45 + 24 + 14) ÷ 1.0 = 83. This tool handles any number of value-weight pairs.

Formula & method

For each row the tool multiplies the value by its weight and sums these products to get Σ(value × weight). It also sums the weights to get Σ(weight). The weighted average is the first sum divided by the second. Rows missing a value or weight are ignored, and a total weight of 0 leaves the mean undefined.

Examples

Example 1: Three weighted scores
Input
90×0.5, 80×0.3, 70×0.2
Result
83
Why
(45 + 24 + 14) ÷ (0.5 + 0.3 + 0.2) = 83 ÷ 1 = 83.
Example 2: Course grade by credits
Input
95×3, 85×4, 75×2
Result
≈ 86.11
Why
(285 + 340 + 150) ÷ (3 + 4 + 2) = 775 ÷ 9 ≈ 86.11.
Example 3: Equal weights = plain mean
Input
4×1, 8×1, 6×1
Result
6
Why
With equal weights the weighted average equals the ordinary average: 18 ÷ 3 = 6.

When to use this tool

  • Computing a GPA or course grade where assignments carry different weights.
  • Averaging prices by quantity, or ratings by number of reviews.
  • Combining survey or portfolio components that matter unequally.

Common mistakes

  • Dividing by the number of items instead of by the sum of the weights.
  • Forgetting that weights need not sum to 1 — the formula divides by their total either way.
  • Leaving a value without its matching weight, so that row is skipped.

Frequently asked questions

What is a weighted average?

An average where each value contributes according to its weight. It equals Σ(value × weight) ÷ Σ(weight), giving more influence to higher-weighted items.

Do the weights have to add up to 1?

No. They can be any positive numbers — credits, quantities, percentages — because the formula divides by the total weight.

How is it different from a normal average?

A normal average treats every value equally. A weighted average lets some values count more, and the two are equal only when all weights are the same.

Can I add more rows?

Yes. Use 'Add row' to include as many value-weight pairs as you need, and remove rows you don't.

What if my total weight is 0?

Then the weighted average is undefined, because the formula would divide by zero. Give at least one row a non-zero weight.

Are rows without a weight ignored?

Yes. Any row missing a value or a weight is skipped so it doesn't distort the result.

Sources & references

External references open in a new tab. We are independent and not affiliated with these organizations.

  • ✓ Free to use
  • ✓ No sign-up required
  • ✓ Runs entirely in your browser — nothing is uploaded.
  • ✓ Formula and method shown above
Last updated: How we calculateReport a correctionDisclaimer

Provided “as is” for general information only — results may be inaccurate, so verify before you rely on them. No warranty; use at your own risk.

Built and reviewed by HIFreeTools against the formula shown above and any authoritative references cited on this page. See our methodology and editorial standards.

Related tools

Embed this tool on your site

Free to embed, no sign-up. Paste this code where you want the weighted average calculator to appear: