Weighted Average Calculator — Formula
## Weighted Average
### Formula
**Weighted Average = (v₁w₁ + v₂w₂ + ... + vₙwₙ) / (w₁ + w₂ + ... + wₙ)**
Each value is multiplied by its weight, summed, then divided by the total weight.
### When to Use
Use weighted averages when different items contribute unequally: course grades (different credit hours), stock portfolio returns (different investment amounts), or survey responses (different sample sizes).
### Formula
**Weighted Average = (v₁w₁ + v₂w₂ + ... + vₙwₙ) / (w₁ + w₂ + ... + wₙ)**
Each value is multiplied by its weight, summed, then divided by the total weight.
### When to Use
Use weighted averages when different items contribute unequally: course grades (different credit hours), stock portfolio returns (different investment amounts), or survey responses (different sample sizes).
Esempio Risolto
Three scores: 85 (weight 3), 92 (weight 4), 78 (weight 2).
- Weighted sum = 85×3 + 92×4 + 78×2 = 255 + 368 + 156 = 779
- Total weight = 3 + 4 + 2 = 9
- Weighted average = 779/9 ≈ 86.5556
- Simple average = (85+92+78)/3 = 85