Statistics Calculators
Standard deviation with every step, z-scores and normal probabilities, confidence intervals and survey sample sizes, percentiles, probability, permutations and combinations — accurate to many decimal places, so you do not need a printed table.
62 calculators · A–Z of all calculators
- Standard Deviation CalculatorSample and population standard deviation, with steps.
- Coefficient of Variation CalculatorRelative standard deviation in percent.
- Z-Score CalculatorZ-score, percentile and normal curve probabilities.
- Normal Distribution CalculatorProbabilities and percentiles of a bell curve.
- Probability CalculatorTwo events — both, either, neither — and at least once.
- Bayes’ Theorem CalculatorPositive predictive value of a test.
- Permutation and Combination CalculatornPr and nCr, with or without repetition.
- Confidence Interval CalculatorConfidence interval for a mean with t or z.
- Margin of Error CalculatorMargin of error for a poll or survey.
- Sample Size CalculatorHow many survey responses you need.
- Percentile CalculatorAny percentile, quartiles and percentile rank.
- Quartile CalculatorQ1, Q3, IQR, five-number summary and outliers.
- Linear Regression CalculatorLine of best fit, slope, intercept and R².
- Correlation Coefficient CalculatorPearson's r, R² and its p-value.
- Spearman Correlation CalculatorRank correlation with ties.
- P-Value CalculatorP-value from a z-score or t-statistic.
- Chi-Square CalculatorGoodness-of-fit test and chi-square p-value.
- Chi-Square Test of IndependenceContingency table chi-square test.
- T-Test CalculatorTwo-sample Welch or Student t-test.
- Paired T-Test CalculatorBefore-and-after matched samples.
- One-Way ANOVA CalculatorF statistic and p-value for groups.
- Two-Proportion Z-Test CalculatorCompare two percentages.
- Effect Size CalculatorCohen’s d and Hedges’ g.
- Odds CalculatorAmerican, decimal and fractional odds to probability.
- Relative Risk & Odds Ratio CalculatorRR and OR with 95% confidence intervals.
- Binomial Probability CalculatorExactly, at least and at most k successes.
- Hypergeometric Distribution CalculatorProbabilities without replacement.
- Poisson Distribution CalculatorProbabilities of event counts.
- Expected Value CalculatorProbability-weighted average of outcomes.
- Covariance CalculatorSample and population covariance.
- Mean Absolute Deviation CalculatorMAD about the mean or median.
- Critical Value Calculatorz, t, chi-square and F cutoffs.
- Fisher’s Exact Test Calculator2×2 table exact p-value.
- Standard Error CalculatorSE of a mean, a proportion or a difference.
- Geometric Distribution CalculatorChance of the first success on trial k.
- Exponential Distribution CalculatorWaiting-time probabilities and percentiles.
- F-Test for Two Variances CalculatorCompare two variances: F, p-value, decision.
- Skewness & Kurtosis CalculatorSample and population skewness and excess kurtosis.
- Dice Probability CalculatorExact odds for the sum of n dice, plus 4d6 drop lowest.
- Statistical Power CalculatorPower and sample size for t-tests and two proportions.
- Sensitivity and Specificity CalculatorTest accuracy from a 2×2 table, with 95% intervals.
- Mann–Whitney U Test CalculatorWilcoxon rank-sum test for two independent samples.
- Empirical Rule Calculator68–95–99.7 rule for any mean and SD, plus Chebyshev.
- Birthday Paradox CalculatorChance two people share a birthday, and hash collisions.
- One-Sample T-Test CalculatorTest a mean against a value: t, p, CI, z-test option.
- Wilcoxon Signed-Rank Test CalculatorNonparametric test for paired samples or one median.
- Moving Average CalculatorSimple, weighted and exponential averages of a series.
- Negative Binomial Distribution CalculatorFailures or trials until the r-th success.
- Cohen’s Kappa CalculatorInter-rater agreement with CI and weighted kappa.
- Kruskal-Wallis Test CalculatorCompare 2-8 groups by ranks: H, p-value, Dunn's test.
- One-Proportion Z-Test CalculatorTest a percentage against a value: z, p, exact test, CIs.
- Poker Odds CalculatorPot odds, outs, EV of a call and starting-hand combos.
- Streak Probability CalculatorExact odds of a run in a row, the longest streak and HH vs HT.
- Dice Expression CalculatorOdds for 2d6+3, advantage and attack damage against AC.
- Standard Score Converterz, T, IQ-style, NCE, stanine, sten and percentile.
- Cronbach’s Alpha CalculatorScale reliability, alpha if item deleted, Spearman–Brown.
- Net Promoter Score CalculatorNPS from promoters and detractors, with confidence interval.
- A/B Test Sample Size CalculatorVisitors per variant for a conversion-rate test.
- Likert Scale CalculatorMean, median, top-2-box and percent agree.
- Survey Response Rate CalculatorAAPOR response rates RR1 to RR6 and more.
- Hardy-Weinberg CalculatorAllele and genotype frequencies, carriers and a chi-square equilibrium test.
- Punnett Square CalculatorMonohybrid, dihybrid and multi-gene crosses with ratios and probabilities.