Average Calculator
0 weighted average
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Weighted Average vs. Simple Average
A weighted average multiplies each value by a weight that reflects its relative importance, sums those products, and divides by the sum of the weights: weighted mean = Σ(value × weight) / Σ(weight). This is the standard method used for a course grade made up of a midterm, final, and homework worth different percentages, or a portfolio return blended across positions of different sizes. The simple average is just the special case where every weight is equal (for example, all set to 1) — it reduces to the ordinary sum of values / count you probably learned first. Enter your value/weight pairs above and this calculator returns both, so you can see exactly how much the weighting changes the result.
A Worked Example: GPA-Style Grading
Suppose you scored 90 on an assignment worth 3 credit hours, 85 on one worth 4 credit hours, 78 on one worth 1 credit hour, and 95 on one worth 2 credit hours. The simple average of the four scores is 87, but the weighted average — which properly gives the 4-credit course four times the influence of the 1-credit course — comes out to a different number. Whenever some inputs should count more than others (credit hours, transaction sizes, sample sizes, survey respondent counts), the weighted average is the mathematically correct choice, not the simple one.
Just Need a Plain List Average?
If your data doesn't have meaningful weights and you also want the median, mode, range, and standard deviation in one place, the statistics calculator covers the full descriptive-statistics summary for a single list of numbers. For the spread of your data around the mean specifically, see the standard deviation calculator.
Frequently Asked Questions
What is the difference between a weighted average and a simple average?
A simple average adds up all the values and divides by how many there are, treating every value equally. A weighted average multiplies each value by a weight reflecting its importance (like credit hours or transaction size), sums those products, and divides by the sum of the weights. A simple average is just a weighted average where every weight happens to be equal.
How do I calculate a weighted grade average with credit hours?
Enter each grade as the value and its credit hours as the weight (for example, "90, 3" for a 90 in a 3-credit course). The calculator multiplies each grade by its credit hours, adds those products together, and divides by the total credit hours to get your weighted GPA-style average.