Weighted Average Calculator
Calculate any weighted average from scores and weights โ weights don't need to add up to 100.
Weighted Average
Enter a score and weight for at least one row to see the weighted average.
The Formula
Weighted Average = ฮฃ(Score ร Weight) รท ฮฃ(Weight)
Each score is multiplied by its own weight before being added together, then the total is divided by the sum of all the weights โ so items with a bigger weight pull the average further toward their own score.
How This Differs From Related Tools
This is the general-purpose version of a weighted average, and it's worth knowing when the more specialized tools on StudyCalc are a better fit. GPA Calculator is this exact same math, purpose-built for course grades and credit hours specifically. The Course Weight Impact Calculator answers a different, narrower question โ not "what's my current average," but "how much could one specific upcoming item move my grade." And Grade Calculator's guide covers the reverse-solve case โ "what score do I need on my final" โ which this tool deliberately doesn't attempt, since it's a forward-calculation-only tool by design.
Worked Example 1: Two Items
Two items: a score of 80 with weight 30, and a score of 90 with weight 70.
Note this isn't the same as the plain average of 80 and 90 (85.0) โ the higher-weighted 90 pulls the result closer to itself.
Worked Example 2: Three Items With Uneven Weights
Three items: 70 with weight 20, 85 with weight 50, and 95 with weight 30.
Here the weights happen to sum to exactly 100, so the calculation reads directly as a percentage-weighted blend โ the middle score (85, at the largest 50% weight) anchors the result almost exactly at its own value, with the other two pulling only slightly in each direction.
Frequently Asked Questions
Do my weights need to add up to 100?
No. The calculator normalizes automatically by dividing the weighted sum by the total weight, so weights of 2, 3, and 5 work exactly the same as 20%, 30%, and 50%.
What can I use this for?
Anything with scores that don't carry equal importance โ course grades weighted by credit hours, portfolio returns weighted by allocation, survey responses weighted by sample size, and similar cases.
Can I find out what score I need on a remaining item to hit a target average?
Not with this tool โ it only calculates the average forward from scores you already have. For "what do I need on my final exam" style questions, use the Grade Calculator's guide, which covers that calculation.
What happens if I leave a row's score or weight blank?
Incomplete rows are skipped automatically and don't affect the result โ only rows with both a score and a weight filled in are counted.
Why does a higher weight pull the average toward that item's score?
Because the formula multiplies each score by its own weight before summing โ an item with a large weight contributes a proportionally larger chunk of the total, so its score has more influence on where the final average lands than a low-weight item's score does.
Is this the same math as a stock portfolio's weighted return?
Yes โ a portfolio's overall return is the weighted average of each holding's return, weighted by how much of the portfolio it makes up. The exact same ฮฃ(value ร weight) รท ฮฃ(weight) formula applies whether the "values" are course scores, investment returns, or survey responses.
Can weights be negative?
No โ a weight represents how much something counts, and a negative weight doesn't have a sensible real-world meaning in this context. The calculator only accepts weights greater than 0.
How is this different from just averaging all the scores normally?
A normal (unweighted) average treats every score as equally important, dividing the sum by the count of items. A weighted average lets some items count more than others โ the two only give the same result when every item happens to carry an identical weight. Use the Letter Grade Average Calculator specifically if you want a simple, unweighted average of letter grades instead.
What's a sensible way to choose weights if none are given to me?
If you're building your own weighting scheme rather than following an instructor's stated one, base weights on genuine relative importance โ time invested, difficulty, or how much a component should count toward the final outcome. There's no single correct system; consistency in how you apply it matters more than the specific numbers chosen.
Related Calculators
Looking for "what score do I need on my final"? Start here.
Course Weight Impact CalculatorSee what one upcoming assessment is worth to your grade.
GPA CalculatorA weighted average specifically for course grades and credit hours.
CGPA CalculatorA weighted average across semesters instead of items.