Statistics Calculators
Descriptive statistics, probability distributions, inference and sampling — enter your data or parameters and get results with formulas.
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Statistics CalculatorMean, median, mode, standard deviation, variance and quartiles of a list.
Permutation & Combination CalculatornPr, nCr and factorials with exact big-number results.
Probability CalculatorProbability of A and B, A or B, complements and repeated trials.
Quartile CalculatorQuartiles, IQR, five-number summary and outliers for a data set.
Percentile CalculatorThe value at any percentile, or the percentile rank of a value.
Z-Score CalculatorConvert values to z-scores and find normal probabilities and percentiles.
Confidence Interval CalculatorConfidence intervals for a mean (t or z) or a proportion.
Margin of Error CalculatorMargin of error for surveys and sample means, with finite population correction.
Sample Size CalculatorHow many survey responses you need for a given margin of error.
Standard Error CalculatorStandard error of the mean from SD and n, or from raw data.
Correlation Coefficient CalculatorPearson r, r², Spearman ρ and significance for paired data.
Linear Regression CalculatorLeast-squares line of best fit, R² and predictions.
Normal Distribution CalculatorProbabilities below, above or between values, and inverse normal.
Binomial Probability CalculatorExact and cumulative binomial probabilities.
Random Sample GeneratorDraw a random sample from a number range or your own list.
Random Assignment GeneratorRandomly assign participants to balanced groups or treatments.
A/B Test Sample Size CalculatorVisitors needed per variant to detect a conversion lift.