Weighted Average Calculator
Find the mean of values where each one counts by its own weight.
How the weighted average works
A weighted average gives each value its own importance (weight) in the final result, unlike a plain average where every value counts equally. It is used whenever some inputs should matter more than others — course grades weighted by credit hours, scores weighted by category, or portfolio returns weighted by allocation.
Add each value with its weight. The calculator multiplies every value by its weight, sums the results, and divides by the total weight.
Weights don't need to sum to 1 or 100 — the formula normalizes automatically by dividing by the total weight, so you can use raw weights like credit hours, sample sizes or dollar amounts directly.
The formula
Weighted average = Σ(value × weight) ÷ Σ(weight)
Multiply each value by its weight, add all those products together, then divide by the sum of the weights.
Worked example
Two grades: 90 at 30% weight, 80 at 70% weight
(90 × 0.3) + (80 × 0.7) = 27 + 56 = 83, divided by (0.3 + 0.7) = 1 → weighted average of 83.
Frequently asked questions
Do my weights need to add up to 100% or 1?
No. The formula divides by the total weight, so raw weights like credit hours (3, 4, 3) or dollar amounts work directly without converting to percentages first.
What happens if all weights are equal?
A weighted average with equal weights gives exactly the same result as a plain (unweighted) average — the weighting has no effect when every value counts the same.
Can a weight be zero?
Yes for an individual value (it is simply excluded from the result), but the total of all weights must be greater than zero, since dividing by a zero total is undefined.
Related tools
Built by PanelRoster
PanelRoster is an enterprise operations management platform for organizations coordinating distributed teams, assignments, workflows, quality assurance and operational execution.
Explore PanelRoster