What is the difference between mean, median, and mode?

Mean (average): sum ÷ count. Median: middle value when sorted (most useful for skewed data like income). Mode: most frequent value. Use median for data with outliers; use mean for normally distributed data.

What is standard deviation?

Standard deviation measures how spread out values are from the mean. A low SD means values are clustered near the mean; high SD means they are spread out. For a normal distribution, ~68% of values fall within 1 SD of the mean.

How do I find the average of my test scores?

Add all the scores together and divide by how many there are. For scores of 80, 90 and 100, the mean is 270 ÷ 3 = 90. Paste your numbers into the tool and it returns the mean instantly, along with the median, mode and standard deviation.

Should I use the mean or the median for grades?

The mean is fine when scores are fairly even. If one very low score (such as a missed test scored 0) drags the average down, the median — the middle value when sorted — better reflects typical performance. The tool shows both so you can compare.

What is the geometric mean used for?

The geometric mean multiplies all the values and takes the nth root, making it the right average for growth rates, ratios and percentages that compound, such as annual returns. For ordinary test scores the arithmetic mean is the appropriate measure.

What does the 68-95-99.7 rule mean?

For a normal (bell-shaped) distribution, about 68% of values fall within one standard deviation of the mean, 95% within two, and 99.7% within three. It is a quick way to judge how unusual a value is once you know the mean and standard deviation.

Average Calculator — Mean, Median, Mode & Range

How to use Average / Mean Calculator

The average calculator computes a full set of descriptive statistics — mean, median, mode, range, variance, standard deviation and geometric mean — from a comma-separated list of numbers. It also shows sorted values and, for larger datasets, a frequency distribution chart. Use it for grading, survey analysis, finance or any data set where a quick statistical summary is needed.

Enter numbers separated by commas, spaces or new lines in the input box.
Statistics update automatically as you type.
For larger datasets, a frequency distribution is shown below the summary.
Copy any individual statistic or download the full summary.

Your data never leaves your device — 100% private processing.

Mean, median and mode — when each matters

The mean is sensitive to outliers: one very large value can pull it far from the centre. The median (middle value when sorted) is resistant to outliers and better represents typical values in skewed distributions like income or house prices. Mode (most common value) is most useful for categorical or discrete data. For symmetric distributions all three measures converge; for skewed data they diverge significantly.

Standard deviation and variance

Variance is the average squared deviation from the mean. Standard deviation (the square root of variance) restores the original units and represents typical spread. A dataset of [10, 10, 10] has SD = 0; [1, 10, 19] has SD ≈ 7.4. The "68-95-99.7 rule" states that for a normal distribution, approximately 68% of values fall within ±1 SD, 95% within ±2 SD and 99.7% within ±3 SD.

Statistical measures — when to use each
Measure	Formula (simplified)	Best used for
Mean	Sum ÷ count	Symmetric distributions; no outliers
Median	Middle value (sorted)	Skewed data: income, house prices
Mode	Most frequent value	Categorical or discrete data
Range	Max − Min	Quick spread check
Std. deviation	√Variance	Quantifying spread in same units as data
Variance	Σ(x − mean)² ÷ n	Theoretical analysis; input to other stats

Worked examples

Average of test scores

Inputs: 80, 90, 100

Result: mean 90 · median 90

Outlier skews the mean

Inputs: 30, 35, 40, 500

Result: mean 151.25 · median 37.5

Standard deviation

Inputs: 1, 10, 19

Result: mean 10 · σ ≈ 7.35

Glossary

Mean: Sum of all values divided by count; the arithmetic average.
Median: The middle value when the dataset is sorted in order.
Mode: The value that appears most frequently in the dataset.
Standard deviation: A measure of how spread out values are around the mean.
Variance: The average of squared deviations from the mean.

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Average / Mean Calculator

How to use Average / Mean Calculator

Mean, median and mode — when each matters

Standard deviation and variance

Worked examples

Glossary

Related reading

Frequently Asked Questions

Why use Average / Mean Calculator?

Common use cases

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