Weighted Average Calculator
Calculate a weighted average or weighted mean from values and weights โ paste from a spreadsheet, see each item's contribution.
๐ Runs entirely in your browser โ nothing is uploadedHow a weighted average is calculated
A weighted average, also called a weighted mean, combines several values when some of them matter more than others. Each value is multiplied by its weight, the products are added together, and that total is divided by the sum of all weights: weighted average = ฮฃ(value ร weight) รท ฮฃ weights. If all the weights are equal, the result is the same as the ordinary mean. When one item has a much larger weight, the result moves toward that item's value.
Because the formula divides by the total weight, the weights do not need to add up to 100 or to 1. Course weights of 20 %, 15 %, 25 % and 40 % give the same answer as 0.2, 0.15, 0.25 and 0.4, or as credit hours. The table under the result shows every item's share of the total weight and its contribution to the final number, so you can see which items drive the average and how much an improvement in one of them would change it.
Common uses
Students use weighted averages to compute a course grade from assignments, quizzes and exams with different weights, or a GPA from grades and credit hours. Investors use them to find the average purchase price of shares bought at different prices and quantities, or the weighted return of a portfolio. Businesses compute weighted average cost, survey analysts weight responses by group size, and teachers combine rubric criteria with different importance.
To enter data, put one item per line with the value followed by the weight. A label at the start of the line is optional and is only used in the table. Commas, semicolons, tabs and spaces are all accepted as separators, and a percent sign after the weight is ignored, so two columns pasted from Excel or Google Sheets work directly. Use a dot as the decimal separator. Lines that cannot be read are skipped and listed under the result. All calculations happen in your browser.
How to use
- Enter one item per lineType or paste a value and its weight on each line, optionally with a label first, e.g. โMidterm, 82, 25%โ.
- Use any separatorCommas, semicolons, tabs or spaces all work, so you can paste two columns straight from a spreadsheet.
- Read the weighted averageSee the weighted average, the sum of weights and each item's share and contribution in the table.