Statistics
Statistics Calculators
Correlation, regression, probability distributions, and variability measures.
28 tools
Average Return Calculator
Average return calculator: simple average of yearly returns. Free average return calculator with the formula shown - runs entirely in your browser, no signup.
Bayes Theorem Calculator
Bayes theorem calculator: update a prior probability into a posterior using test sensitivity, specificity, and base rate for risk decisions. Free, no signup.
Binomial Probability Calculator
Binomial probability calculator: compute exact, at least, and at most outcomes for n trials with success probability p. Free, runs in your browser offline.
Chi-Square Goodness of Fit Calculator
Chi square goodness of fit calculator: test if observed counts match expected distributions and get the statistic and p-value. Free, runs locally, no signup.
Cohen's D Calculator
Cohen's d calculator measures effect size between two groups from means and standard deviations, with interpretation. Free, private, runs in your browser.
Combinations and Permutations Calculator
Combinations and permutations calculator: compute nCr and nPr with or without repetition, with formula steps shown. Free, no signup, runs locally in browser.
Conditional Probability Calculator
Conditional probability calculator computes P(A|B) from event probabilities with clear Bayes working shown. Free, private, runs locally in your browser.
Correlation Coefficient Calculator
Correlation coefficient calculator: compute Pearson r from paired x and y data to see how strongly two variables move together. Free, private, no signup.
Expected Value Calculator
Expected value calculator: multiply each outcome by its probability and sum them for the EV of any bet or decision. Free, no signup, runs in your browser.
Five Number Summary Calculator
Five number summary calculator: minimum, lower and upper quartiles, median, maximum, plus IQR and outlier flags from your data set. Free, in your browser.
Geometric Distribution Calculator
Geometric distribution calculator: compute probability of first success on trial n, mean, and variance. Free, private, runs locally in your browser, no signup.
Geometric and Harmonic Mean Calculator
Geometric mean calculator: compute geometric and harmonic means for growth rates, investment returns, and ratios. Free, private, runs locally, no signup.
Harmonic Mean Calculator
Harmonic mean calculator: n divided by the sum of reciprocals. Free harmonic mean calculator with the formula shown - runs entirely in your browser, no signup.
IQR Calculator
iqr calculator that finds the interquartile range, Q1, Q3, and outliers for any data set and shows the five-number summary. Free, private, runs in your browser.
Independent Events Calculator
Independent events calculator: compute the combined probability of multiple independent events happening together, step by step. Free, no signup, runs in browser.
Linear Regression Calculator
Linear regression calculator: fit a least squares line to x and y data and get slope, intercept, r, and r2 values. Free, private, no signup, runs locally.
Margin of Error Calculator
Margin of error calculator: compute survey margin of error from sample size, confidence level, and population size. Free, private, no signup, in your browser.
Moving Average Calculator
Moving average calculator: simple moving average of a series. Free moving average calculator with the formula shown - runs entirely in your browser, no signup.
Normal Distribution Probability Calculator
Normal distribution probability calculator: find area under the bell curve between z scores or raw values. Free, editable mean and SD, runs locally offline.
Odds Ratio Calculator
Odds ratio calculator: compute odds ratio, 95% confidence interval, and p-value from a 2x2 table. Free, private, runs locally in your browser, no signup.
Outlier Calculator
Outlier calculator: find outliers in a data set using the IQR rule and z-scores, showing which values fall outside normal bounds and why. Free, runs locally.
P Value Calculator
P value calculator: get exact p values from z, t, chi-square, or F test statistics for hypothesis testing. Free, private, runs in your browser, no signup.
Percentage Error Calculator
Percentage error calculator: compare a measured value to the true value and get percent error instantly. Free, private, runs locally in your browser, no signup.
Permutation Combination Calculator
Permutation and combination calculator: nPr and nCr. Free permutation combination calculator with the formula shown - runs entirely in your browser, no signup.
Poisson Probability Calculator
Poisson probability calculator: compute exact event probabilities from a mean rate, including P(X=k) and cumulative ranges. Free, runs locally, no signup.
Skewness Calculator
Skewness calculator: compute sample skewness and kurtosis for any data set with a plain-language interpretation. Free, private, runs locally, no signup.
T Test Calculator
t test calculator that runs one-sample, two-sample, and paired t-tests and returns t-statistics, p-values, and significance. Free, private, runs in your browser.
Z Test Calculator
Z test calculator: z-score for a sample mean vs a known population. Free z test calculator with the formula shown - runs entirely in your browser, no signup.