Average Calculator
Calculate mean, median, mode, and range from a list of numbers.
Frequently Asked Questions
What is the difference between mean, median, and mode?
Mean is the arithmetic average — sum of all values divided by count. Median is the middle value when all numbers are sorted; for an even count, it's the average of the two middle values. Mode is the most frequently occurring value (a dataset can have multiple modes or none). Each measure describes the centre of a dataset differently.
When should I use median instead of mean?
Use the median when data is skewed or contains outliers. Average household income is a classic example: a few billionaires dramatically inflate the mean, making it unrepresentative of typical income. The median ignores extremes and reflects the middle of the distribution. For symmetric, bell-curve data, mean and median are nearly identical.
What is standard deviation and what does it tell me?
Standard deviation measures how spread out values are from the mean. A low standard deviation means values cluster tightly around the mean; a high standard deviation means they are widely spread. In finance, standard deviation measures investment volatility. In quality control, it measures process consistency. Roughly 68% of data falls within one standard deviation of the mean in a normal distribution.
What is the range and when is it useful?
Range = maximum value − minimum value. It is the simplest measure of spread — a single number showing the total span of the data. It is easy to calculate but sensitive to outliers. A dataset of [1, 2, 3, 4, 100] has a range of 99, which overstates the typical spread. For datasets with outliers, use interquartile range (IQR) instead.