Weighted Average Calculator
Some numbers matter more than others. Enter each value with its weight and get a mean that respects how much each one counts.
How it works
A weighted average multiplies each value by its weight, adds those products, and divides by the sum of the weights. Bigger weights pull the result toward their values.
The formula is (Σ value × weight) / (Σ weight). If every weight is equal, it collapses back into a plain average — the weighting only changes things when some entries carry more importance than others.
Say an exam is 90 with weight 3, a quiz is 80 with weight 2, and homework is 70 with weight 1. That's (90×3 + 80×2 + 70×1) / (3+2+1) = 500 / 6 ≈ 83.3, higher than the simple average of 80 because the heaviest slice scored best.
Frequently asked questions
How is this different from a normal average?
A normal average treats every number as equally important. A weighted average lets you say some values count more — a final exam worth 40% of a grade, or a large fund in a portfolio — so those entries have more say in the result.
Do the weights have to add up to 100?
No. Weights can be any numbers — 3, 2, 1 works fine, and so do percentages or dollar amounts. The tool divides by whatever the weights total, so their scale doesn't matter, only their proportions to each other.
What if all my weights are the same?
Then you'll get the ordinary average. Equal weights give every value identical pull, which is exactly what a plain mean does. The weighting only shifts the answer when the weights differ.
Why is the result a dash?
That shows up when the weights sum to zero or no complete rows are filled in, since dividing by a total weight of zero has no answer. Add at least one row with a real value and a non-zero weight and the average appears.