Quick answer
The mean is the sum divided by the count: x̄ = Σx ÷ n. The values 4, 8, 15, 16, 23 and 42 sum to 108, so the mean is 18.
Enter a list of numbers. The calculator returns the arithmetic mean.
Related tools: Mean Median Mode Calculator: Mean, median and mode of a data set. Standard Deviation Calculator: Sample or population standard deviation with variance and mean. Z-Score Calculator: Standardize a value using a mean and standard deviation.
How to use the Mean Calculator
- Type data set, for example 4, 8, 15, 16, 23, 42.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Data set | Text, such as 4, 8, 15, 16, 23, 42 | — |
Formula and method
Formula
mean = Σx ÷ n
IEEE-754 double precision; shown to at most 6 decimal places.
Computed directly from the sorted or raw values.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Data set = 4, 8, 15, 16, 23, 42.
| Result | Value |
|---|---|
| Mean | 18 |
Example 2
Inputs: Data set = 1 2.
| Result | Value |
|---|---|
| Mean | 1.5 |
The first line is the headline result (mean). IEEE-754 double precision; shown to at most 6 decimal places.
What the mean tells you
The mean is the balance point of the data. A single large value pulls it up: without the 42 the mean of the other five is 13.2. For skewed data the median describes the typical value better.
Related averages
The geometric mean suits growth rates and the harmonic mean suits rates. For weighted data use the Weighted Average calculator. At least one value is needed.
The mean and outliers
The mean of 4, 8, 15, 16, 23, 42 is 108 ÷ 6 = 18. It uses every value, so one extreme value moves it: replacing 42 with 420 raises the mean to 81.
Adding the same constant to every value raises the mean by that constant, and multiplying every value by k multiplies the mean by k. The mean has the same unit as the data.
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Data set: left empty shows "Enter data set." beside that field and no result.
Choosing between the Mean Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Mean Median Mode Calculator](/statistics/mean-median-mode-calculator/) | data set | Mean |
| [Standard Deviation Calculator](/statistics/standard-deviation-calculator/) | data set and data type | Population standard deviation (σ) |
| [Z-Score Calculator](/statistics/z-score-calculator/) | value, mean and standard deviation | Z-score |
| [Confidence Interval Calculator](/statistics/confidence-interval-calculator/) | sample mean, standard deviation and sample size | Confidence interval |
| [Geometric Mean Calculator](/statistics/geometric-mean-calculator/) | data set | Geometric mean |
Background: descriptive statistics
Population statistics divide by n and sample statistics divide by n − 1 (Bessel's correction), because a sample tends to understate variability. Use the population version when your data is every value in the group, and the sample version when it is a subset.
Defaults differ between tools, and so do quartile conventions, which can give slightly different values for small data sets; this page states the method it uses.
Assumptions and limitations
- At least one value
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for data set to confirm this.
Frequently asked questions
What is the mean of 2, 4, 6?
The mean of 2, 4 and 6 is 12 ÷ 3 = 4.
Is the mean always a data value?
No. The mean can be a value that never occurs, like 2.5 children per family.
How do outliers affect it?
They pull it strongly.
Is the mean the same as the average?
In everyday use, average usually means the arithmetic mean. Strictly, the median and mode are also averages.
What happens to the mean if I add 10 to every value?
The mean also increases by 10, because every value moved up by the same amount.
What does the Mean Calculator calculate?
Mean of a data set. It returns Mean.
What formula does the Mean Calculator use?
mean = Σx ÷ n. Computed directly from the sorted or raw values.
What is an example of a mean result?
With data set 4, 8, 15, 16, 23, 42, the mean is 18.
Related calculators
- Mean Median Mode Calculator — Mean, median and mode of a data set.
- Standard Deviation Calculator — Sample or population standard deviation with variance and mean.
- Z-Score Calculator — Standardize a value using a mean and standard deviation.
- Confidence Interval Calculator — Confidence interval for a mean (t or z).
- Geometric Mean Calculator — Geometric mean of a data set.
- Harmonic Mean Calculator — Harmonic mean of a data set.
- Mean Absolute Deviation Calculator — Average distance of values from the mean.
- Mean Median Mode Range Calculator — Mean, median, mode and range of a data set.
- Descriptive Statistics Calculator — Count, mean, median, mode, spread, quartiles and range in one place.
Sources
- OpenStax, Introductory Statistics 2e (Rice University): measures of center and spread, correlation and regression
- NIST/SEMATECH e-Handbook of Statistical Methods (nist.gov), Exploratory Data Analysis chapter
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.