Average Calculator
Find the average (mean) of a list of numbers, or compute a weighted average from values and weights. Shows the sum, count, and the result instantly.
Average (mean)
86.2
Sum
431
Count
5
A simple average adds all the numbers and divides by how many there are. A weighted average multiplies each value by its weight, sums those products, and divides by the total weight — useful for grades, where some assignments count more than others.
Frequently Asked Questions
How do I calculate the average of a list of numbers?
Add all the numbers together to get the sum, then divide by how many numbers there are. For example, the average of 4, 8, and 9 is (4 + 8 + 9) ÷ 3 = 7. Just paste your numbers above and the calculator does it instantly.
What is the difference between average and mean?
In everyday math they are the same thing: the arithmetic mean. Statisticians use 'mean' more precisely because there are other kinds of averages (median and mode), but when someone says 'the average,' they almost always mean the sum divided by the count.
How does a weighted average work?
A weighted average gives some values more importance than others. Multiply each value by its weight, add up those products, and divide by the sum of the weights. For example, with grades weighted 50%, 30%, and 20%, a 90/80/70 gives (90×0.5 + 80×0.3 + 70×0.2) ÷ 1 = 83.
When should I use a weighted average instead of a simple one?
Use a weighted average whenever the items don't count equally — final exams worth more than quizzes, larger purchases in an average price, or survey responses with different sample sizes. A simple average treats every value the same.
Do the weights have to add up to 1 or 100%?
No. The calculator divides by the total of the weights, so any consistent scale works. Weights of 5, 3, 2 give the same result as 0.5, 0.3, 0.2 or 50, 30, 20.