Weighted Average Calculator
Calculate weighted average from any set of values and their respective weights. Perfect for GPA, investment portfolios, and performance metrics.
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Enter weights separated by commas (must match number of values)
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What is a weighted average?
A weighted average assigns different weights to values based on their importance. Instead of summing values and dividing by count (simple average), you multiply each value by its weight, sum those products, then divide by the total weight. For example, a final exam worth 40% of your grade matters more than a quiz worth 10%.
How is weighted average different from simple average?
Simple average (mean) treats all values equally: (85 + 90 + 78) / 3 = 84.3. Weighted average accounts for importance: 0.2×85 + 0.3×90 + 0.5×78 = 83.6 (if weights sum to 1.0). When weights don't sum to 1.0, you divide by total weight. The difference is significant when values have different levels of importance.
Why do my weights need to sum to 1.0?
They don't need to, but it makes interpretation easier. Weights of 0.2, 0.3, 0.5 sum to 1.0 and directly represent percentages. Weights of 2, 3, 5 also work mathematically (divide by 10 total), but 0.2, 0.3, 0.5 is more intuitive. The calculator accepts any weights and normalizes them automatically.
What weights should I use for GPA calculation?
For GPA, use credit hours as weights. If you have 3 credits of A (4.0), 4 credits of B (3.0), and 3 credits of A- (3.7): (3×4.0 + 4×3.0 + 3×3.7) / 10 = 49.1 / 10 = 4.91 weighted GPA. Or with grade points that sum to 1.0: 0.3×4.0 + 0.4×3.0 + 0.3×3.7 = 3.51.