Statistics Calculators
Averages, spread, probability, z-scores and confidence intervals.
- Mean, Median and Mode CalculatorType or paste a list of numbers.
- Z-Score CalculatorChoose whether you know a value with its mean and standard deviation, or you already have a z-score.
- Permutation and Combination CalculatorEnter the total number of items n and how many you choose, r.
- Probability CalculatorEnter the chance of event A and event B as percentages, and the number of times you try A.
- Linear Regression CalculatorEnter your x values and your y values, in the same order, and optionally an x to predict from.
- Confidence Interval CalculatorEnter the sample mean, the sample standard deviation, the sample size and the confidence level.
- Sample Size CalculatorChoose a confidence level, a margin of error and the proportion you expect.
How these statistics calculators work
Most statistics questions start with a summary of the data. The Mean, Median and Mode Calculator gives the center, and the spread comes from the variance and standard deviation. Check whether your data is a whole population or a sample from one: the sample version divides by n minus 1 instead of n, which gives a slightly larger spread. The Z-Score Calculator turns a value into the number of standard deviations from the mean, which is how you compare values from different scales.
The Probability Calculator gives the chance of both, either or neither of two events and of at least one success over several tries, and the Permutation and Combination Calculator counts arrangements: permutations nPr = n! / (n − r)! when order matters and combinations nCr = n! / (r! (n − r)!) when it does not. The Linear Regression Calculator fits a least-squares line, the Confidence Interval Calculator gives a range for a mean, and the Sample Size Calculator tells you how many responses you need. Each page shows its formula, so you can check the method.