Weighted Average Calculator
A weighted average counts each value by its weight: 90, 82 and 75 weighted 50/30/20 average to 84.6.
Percentages, credits or counts; they do not need to add to 100.
84.6
- Σ value × weight
- 8460
- Σ weights
- 100
- Unweighted mean (for comparison)
- 82.33333333
Step-by-step solution
- Weighted average = Σ(xᵢ·wᵢ) ÷ Σwᵢ
- = (90×50 + 82×30 + 75×20) ÷ 100
- = 8460 ÷ 100 = 84.6
Weighted Average Formula
x̄w = Σ(xᵢ·wᵢ) ÷ Σwᵢ
weights can be percentages, credits or counts
Worked Example
Scores of 90, 82 and 75 weighted 50%, 30% and 20%:
- Weighted average = Σ(xᵢ·wᵢ) ÷ Σwᵢ
- = (90×50 + 82×30 + 75×20) ÷ 100
- = 8460 ÷ 100 = 84.6
Σ weights: 100 · Unweighted mean (for comparison): 82.33333333
Test-day tip
Combined-average questions are common on the SAT: two classes with means 80 (20 students) and 90 (30 students) have a combined mean of 86, not 85.
More Problem-Solving and Data Analysis Calculators
-
Mean, Median and Mode Calculator
mean = Σx ÷ n
median: middle value of the sorted data; mode: most frequent value; range = max − min
Example: The data 4, 8, 6, 5, 3, 8, 9, 5, 8: Mean = 6.222222222.
-
Ratio and Proportion Calculator
a : b = c : x ⇒ x = b·c ÷ a
cross-multiplication
Example: The proportion 3 : 4 = 15 : x: x = 20.
-
Probability Calculator
P(A or B) = P(A) + P(B) − P(A and B)
independent: P(A and B) = P(A)P(B); P(A|B) = P(A and B)/P(B)
Example: Independent events with P(A) = 0.5 and P(B) = 0.4: P(A or B) = 0.7.
Frequently asked questions
What score do I need on the final to reach a target grade?
Solve target = (current × current weight + x × final weight) ÷ total weight for x.
How do I combine the means of two groups?
Weight each group mean by its size: (n₁x̄₁ + n₂x̄₂) ÷ (n₁ + n₂). Averaging the two means directly is wrong unless the groups are equal.
Sources
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Weighted Average Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/weighted-average-calculator/
IEEE
Scientific Converters, "Weighted Average Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/weighted-average-calculator/