About the Average Calculator
An average calculator finds the arithmetic mean of a set of numbers — the total divided by how many there are. It is the standard summary of a dataset and the starting point for almost all statistical description, from test scores to monthly expenses.
The formula
Mean = (x₁ + x₂ + … + xₙ) / nEach x is one value in your dataset and n is the count of values. The result is the value each item would have if the total were shared equally.
How to use this calculator
- 1Enter your Number 1. The field starts at
10, which you can overwrite. - 2Enter your Number 2. The field starts at
20, which you can overwrite. - 3Enter your Number 3. The field starts at
30, which you can overwrite. - 4Enter your Number 4. The field starts at
40, which you can overwrite. - 5Enter your Number 5. The field starts at
50, which you can overwrite. - 6Read the result straight away — it recalculates as you type, so there is no button to press. Use Share to copy a link that reopens the page with your exact numbers filled in.
Worked example
| Input | Value |
|---|---|
| Number 1 | 10 |
| Number 2 | 20 |
| Number 3 | 30 |
| Number 4 | 40 |
| Number 5 | 50 |
Result
Mean (Average): 30.0000
Median: 30
Min: 10 | Max: 50
Range: 40
Sum: 150
Those are the values the page loads with, so you can reproduce this result yourself and then change one field at a time to see what drives the outcome.
Understanding your result
The mean is the balance point of the data, which is exactly why it is sensitive to extremes. A single outlier drags it, sometimes badly: four salaries of 40,000 and one of 500,000 give a mean of 132,000, a figure that describes nobody in the group. The median — the middle value — resists that distortion, which is why income and house price statistics are usually reported as medians.
A mean also hides the spread. Datasets of 50, 50, 50 and 0, 50, 100 share a mean of 50 but describe completely different situations. Reporting the standard deviation alongside the mean is what makes the summary informative rather than merely tidy.
Things worth knowing
- Check whether your data has outliers before trusting the mean. If it does, report the median too.
- A weighted average is needed when values carry different importance, such as course credits in a GPA.
- You cannot average averages unless the groups are the same size. Combine the underlying totals instead.
- For rates and ratios such as speeds, the harmonic mean is often the correct measure rather than the arithmetic one.
- The mean of percentages is only meaningful when each percentage is calculated from the same base.
Frequently asked questions
What is the difference between mean, median, and mode?+
The mean is the total divided by the count. The median is the middle value when sorted. The mode is the most frequent value. They coincide in symmetric data and diverge when the data is skewed.
When should I use the median instead of the mean?+
When your data is skewed or contains outliers. Income, house prices, and response times are almost always reported as medians because a few very large values would otherwise distort the mean.
How do I calculate a weighted average?+
Multiply each value by its weight, add the results, and divide by the sum of the weights. A GPA is the classic example: each grade is weighted by the credit hours of its course.
Can the mean be a value that is not in the dataset?+
Yes, and usually it is. The mean of 1, 2, and 4 is 2.33, which appears nowhere in the data. The mean describes the set as a whole rather than naming a member of it.