Weighted Average Calculator
Enter each value with its weight on a line. The weights can be percentages, credits, quantities or any numbers. You get the weighted average and the working.
Type the value first, then the weight. The weights do not need to add up to 100.
Worked examples
Course grade
80 at 20, 65 at 30, 72 at 50
71.5
7,150 ÷ 100.
Average price
£2 for 10 items, £3 for 30 items
£2.75
(20 + 90) ÷ 40.
About Weighted Average Calculator
A weighted average gives more importance to some values than to others. Each value is multiplied by its weight, the results are added up, and the total is divided by the sum of the weights. It is used for course grades where an exam counts for more than coursework, for the average price per item when you bought at different prices, and for index numbers. Scores of 80 weighted 20%, 65 weighted 30% and 72 weighted 50% give (1,600 + 1,950 + 3,600) divided by 100, which is 71.5.
The weights can be any positive numbers, because dividing by their total scales them for you. Percentages, credits, hours and quantities all work. The page also shows the ordinary average of the values for comparison, so you can see how much the weighting changes the answer. A table lists each line with its product and its share of the total weight, which helps when you want to see which values have the most influence on the result.
How to use Weighted Average Calculator
- Type each value and its weight on its own line, separated by a comma or a space.
- Use any numbers for the weights. They do not need to add up to 100.
- Read the weighted average, the total of the weights and the plain average.
- Check the table for each value's share of the total weight.
Common uses
- Working out a course grade from weighted components
- Finding an average price per unit
- Weighted scores in a decision or review
- Averaging rates across groups of different sizes
Frequently asked questions
How do I calculate a weighted average?
Multiply each value by its weight, add up the products, then divide by the total of the weights.
Do the weights have to add up to 100?
No. The calculation divides by the total, so any positive weights work. The share column shows each weight as a percentage of the total.
How is it different from a normal average?
A normal average counts every value equally, which is the same as giving every value a weight of 1. A weighted average lets some count for more.
Can I use it to find an average price per item?
Yes. Enter each price as the value and the quantity bought at that price as the weight.
Can weights be zero or negative?
A weight of zero simply leaves the value out. Negative weights are not allowed.