Average (Mean) Calculator
The mean is the most used — and most misused — statistic: one extreme value can drag it far from typical. This average calculator shows the mean alongside the median, so you can see at a glance whether outliers are distorting your data.
Paste any list of numbers separated by commas, spaces or semicolons and get the mean, median, sum and count instantly.
Enter valid values to see the results.
Formula
The mean shares the total equally; the median is the middle value with half the data above and half below. For skewed data (incomes, house prices) the median is usually the more honest “typical” value.
What you need
- Enter numbers separated by commas, spaces or semicolons — any mix works.
- Decimal points and minus signs are supported; non-numeric entries will block the result.
- There is no practical limit on list length — paste a whole column of data.
Worked example
Practical tips
- Mean and median far apart signals skewed data — report both, or investigate the outliers.
- For rates and ratios (speeds, returns), the mean of ratios is often wrong; average the underlying totals instead.
- The mode (most frequent value) matters for categorical data like shoe sizes — mean and median are meaningless there.
- Removing outliers is a decision, not a default: document why before you delete data points.
Mean vs median with an outlier
| Data | Mean | Median |
|---|---|---|
| 10, 20, 30 | 20 | 20 |
| 10, 20, 30, 100 | 40 | 25 |
| 10, 20, 30, 1000 | 265 | 25 |
| 5, 5, 5, 5 | 5 | 5 |
Common mistakes
- 1 Quoting the mean for skewed data like salaries, where a few high earners inflate it.
- 2 Averaging percentages or averages without weighting by group size.
- 3 Including blank or text cells from a spreadsheet paste, corrupting the count.
Frequently asked questions
What is the difference between mean and median?
The mean is the sum divided by the count; the median is the middle value when sorted. For symmetric data they are close; with outliers the median is more representative.
How do I calculate an average?
Add all the values and divide by how many there are: 10, 20, 30 → 60 ÷ 3 = 20.
When should I use the median instead of the mean?
Whenever the data has extreme values or a skewed distribution — incomes, property prices, response times. The median then better describes the typical case.
What is a weighted average?
An average where values count proportionally to their weights: course grades, for example, weight the exam more than quizzes. Multiply each value by its weight, sum, and divide by the total weight.