Mean, Median, Mode & Standard Deviation Calculator

Quick start

1. Type or paste your data, separated by commas, spaces or new lines.
2. Read the sorted list, the averages and the spread.
3. Use sample values when your data is a sample from a larger group; use population values when it is the whole group.

Example: test scores

Scores: 6, 7, 7, 8, 9, 10, 12. The mean is 59 ÷ 7 ≈ 8.43. The median, the middle value, is 8. The mode is 7, the only repeated score. The range is 12 − 6 = 6.

Standard deviation, step by step

1. Find the mean.
2. Subtract the mean from each value and square the result.
3. Add the squares.
4. Divide by n for a population, or by n − 1 for a sample, to get the variance.
5. Take the square root to get the standard deviation.

The standard deviation is in the same units as your data, so it reads as a typical distance from the mean.

Quartiles and outliers

Q1 marks the lowest quarter of the data and Q3 the top quarter. The interquartile range, Q3 − Q1, covers the middle half. A common rule flags values more than 1.5 × IQR below Q1 or above Q3 as possible outliers.

Which average to use

Use the mean for balanced data, the median when a few extreme values would distort the picture (like house prices or salaries), and the mode for the most common category or size.

Common questions