Tools

Statistics calculator

Paste a sample for its summary statistics, confidence interval and an optional one-sample t-test, or pick a specialized calculator below. Calculations run in your browser; the values you enter aren’t sent to our analytics.

Help me choose a method →Need a reference table? →

Your data (one sample; commas, spaces or new lines)

Confidence level

Test against a mean (optional)

Available calculators

Distributions

Z-Score Calculator

Standardize a measurement or recover a value from z. Interpret the sign and a normal-model percentile without assuming every distribution is normal.

Open calculator ↗Hypothesis Testing

T-Test Calculator

Free t-test calculator for one-sample, two-sample & paired t-tests. Calculate t-value, p-value, degrees of freedom with step-by-step results.

Open calculator ↗Regression

Pearson Correlation Coefficient Calculator

Calculate Pearson's r, R-squared & p-value for any dataset. Free Pearson correlation coefficient calculator with step-by-step interpretation.

Open calculator ↗Descriptive Statistics

Standard Deviation Calculator

Compute sample or population variance and SD. Follow the squared deviations and distinguish individual spread from mean uncertainty.

Open calculator ↗Statistical Tests

One-Way ANOVA Calculator

Compare independent group means with ordinary one-way ANOVA. Get F, degrees of freedom, group summaries and a clear explanation of the limits.

Open calculator ↗Statistical Tests

Bartlett's Test Calculator

Test equal population variances with Bartlett’s statistic. Check independent normal groups and avoid interpreting non-rejection as verified equality.

Open calculator ↗Probability Calculators

Bayes' Theorem Calculator

Update a two-event probability using a base rate and likelihoods. Check compatibility and reproduce a hypothetical file-classification example.

Open calculator ↗Statistical Tests

Chi-Square Independence Calculator

Calculate Pearson chi-square from observed counts. Inspect expected cells, degrees of freedom, association strength and approximation warnings.

Open calculator ↗Probability Calculators

nCr nPr Calculator — Combinations & Permutations

Count ordered and unordered selections with or without repetition. Expand the exact integer and distinguish counts from probabilities.

Open calculator ↗Inferential Statistics

Confidence Interval Calculator

Calculate confidence intervals for population means with this free calculator. Get step-by-step explanations and interpretations.

Open calculator ↗Statistical Calculators

Descriptive Statistics Calculator

Summarize finite data with center, spread and interpolated quartiles. See when skewness, kurtosis and coefficient of variation are undefined.

Open calculator ↗Data Collection

Event Counter & Frequency Tracker

Free online event counter for behavioral observations, research, and data collection. Track multiple events with timing, statistics, and export features.

Open calculator ↗Math Calculators