Weighted average calculator

Enter up to three values and their weights. A larger positive weight gives a value more influence on the result. Blank pairs are ignored; each used pair needs both a value and a positive weight.

Calculate a weighted average

The formula

Weighted average = (value₁ × weight₁ + value₂ × weight₂ + …) ÷ (sum of the weights).

Worked example

Suppose three assessments have scores 7, 8 and 9, with weights 1, 2 and 3. The calculation is (7×1 + 8×2 + 9×3) ÷ (1+2+3) = 50 ÷ 6 ≈ 8.33.

When a weighted average is useful

• School: exams or assignments can count differently toward a final grade. Check the grading rules set by your school.
• Statistics: group averages can be combined using each group’s size as its weight.
• Investing: a weighted purchase price can summarize quantities bought at different prices; it is not the same as investment return.

Common mistakes

• Divide by the sum of the weights, not by the number of values.
• Use values on comparable scales. A score out of 10 and one out of 100 should not be combined without a justified conversion.
• Weights need not add up to 100; the formula divides by their sum.

Frequently asked questions