Statistics calculators

25 free tools

Percentiles, z-scores, probability, and combinations — paste your numbers and get the answer with the formula shown, so you can check the working yourself.

BIBinomial Distribution

Compute P(X=k) and cumulative P(X≤k) for n trials at probability p, along with the mean and variance.

COCoefficient of Variation

Compute the coefficient of variation from a list, or a mean and std dev, as a percentage of the mean.

COConfidence Interval

Build a 90%, 95%, or 99% confidence interval for a mean from the sample mean, standard deviation, and size.

COCorrelation Coefficient

Enter two matching lists of x and y values to get Pearson's r, from -1 to 1, measuring how they move together.

COCovariance

Find the sample and population covariance between two equal-length lists of paired values.

EXExpected Value

Find the expected value of a discrete distribution from paired value and probability lists.

FIFive-Number Summary

Find the minimum, Q1, median, Q3, and maximum of a data set, plus the interquartile range.

GEGeometric Mean

Get the geometric mean of positive numbers, the right average for growth rates and compounding returns.

HAHarmonic Mean

Calculate the harmonic mean of a list, the correct average for rates like speed and P/E ratios.

INInterquartile Range

Paste your numbers to get the quartiles, median, IQR, and the fences that flag outliers.

MEMean Absolute Deviation

Find the mean and the mean absolute deviation, the average distance of your values from the mean.

MEMean Median Mode

Get the mean, median, and mode of a data set at once, plus the count and range.

MIMidrange

Find the midrange of a data set — the average of its smallest and largest values.

NONormal Distribution

Find the z-score and the probabilities P(X<x) and P(X>x) for a value in a normal distribution.

OUOutlier

Find outliers in a data set using the 1.5×IQR rule, with the lower and upper fences shown.

PEPercentile

Drop in a list of numbers, pick a percentile, and see which value sits at that point in the data.

PEPermutation & Combination

Give it n and r and get both nPr and nCr — the count when order matters, and when it doesn't.

PRProbability

Work out the odds of a single event, then combine two events for both, either, or neither.

RARange

Find the minimum, maximum, and range of a data set, along with the count.

RERelative Frequency

Build a frequency table from a data list, showing each value's count, relative frequency, and cumulative frequency.

SASample Size

Find the survey sample size you need from population, confidence level, and margin of error.

STStandard Error

Find the standard error of the mean from a list, or from a standard deviation and sample size.

VAVariance

Paste a list of numbers to get sample variance, population variance, and the mean.

WEWeighted Average

Enter each value with its weight and get a mean that respects how much each one counts.

ZSZ-Score

See how many standard deviations a value is from the mean, and recover the raw value from a z-score.

Frequently asked questions

Which statistics tool should I start with?

Depends on the question. For ranking a value against a group, reach for the Percentile or Z-Score calculator. For counting arrangements, use Permutations & Combinations. For spread, the Interquartile Range tool is a sturdy pick.

Do these show the formula, not just the answer?

Every tool lays out the math it used — the z-score formula, the nPr and nCr expansions, the 1.5×IQR fence rule — right on the page, so you can retrace each step instead of trusting a black box.

Can I paste a whole list of numbers at once?

Go ahead. The percentile and IQR tools take a list separated by commas, spaces, or new lines, filter out anything that isn't a number, and sort the rest for you before doing the math.

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