The average (arithmetic mean) is the sum of the values divided by how many there are.
The average, or arithmetic mean, is the most common way to summarise a set of numbers with a single value. Add every number together and divide by how many numbers there are. It is used everywhere — from working out a test average to a monthly spend or a set of measurements.
How the average is calculated
Average = (sum of all values) ÷ (count of values)
Worked example
For 10, 20, 30 and 40: the sum is 100 and there are 4 numbers, so the average is 100 ÷ 4 = 25.
Mean, median and mode
The mean is only one kind of average. The median is the middle value when the numbers are sorted, and the mode is the value that appears most often. The mean is the best summary when the data is fairly even, but a few very large or very small values can pull it away from the "typical" number, where the median is more robust.
Frequently asked questions
What is the difference between average and mean?
In everyday use they are the same thing — this calculator gives the arithmetic mean, which is what "average" usually means.
How do I enter my numbers?
Type them separated by commas, spaces or new lines. Negative numbers and decimals are fine.
Does the order of the numbers matter?
No. The average is the same whatever order you list the values in.
Can I average percentages?
You can average simple percentages the same way, but if each percentage is based on a different total, a weighted average is more accurate.
