Statistics calculators

21 free calculators for students, researchers and analysts. Each one shows the formula, every step of the working and what the answer means in plain English, and it all runs in your browser, so your data stays on your device.

Not sure which one you need? Answer 2 quick questions

Descriptive statistics

Summarize a set of numbers: the center, the spread and the shape.

  • Sample and population variance from a list of values or a frequency table, with the standard deviation and every step.

Probability & distributions

Probabilities, percentiles and counting, from bell curves to coin flips.

Hypothesis tests

Test whether a difference or a relationship is real, with the p-value explained.

  • Get the p-value from a z, t, chi-square or F statistic, one- or two-tailed, with the reasoning shown.

  • Critical values of z, t, chi-square and F for any significance level, one- or two-tailed.

  • One-sample, two-sample and paired t-tests with the t statistic, p-value, effect size and every step shown.

  • One-way ANOVA for three or more groups: the ANOVA table, F, p-value, effect size and Tukey comparisons, with every step.

  • Test of independence for a table of counts, or goodness of fit, with expected counts, the p-value and every step.

  • One- and two-proportion z-tests, including A/B tests, with the p-value, confidence interval and every step.

Correlation & regression

Measure how two variables move together, and predict one from the other.

Sampling

Plan how many responses you need and estimate values with a margin of error.

  • Confidence intervals for a mean or a proportion, from raw data or summary statistics, with the margin of error explained.

  • Work out how many responses you need for a given confidence level and margin of error.

Business metrics

Survey and customer metrics, worked out with the statistics behind them.

More from StatHow

  • Chart makers: bar graphs, histograms, box plots and scatter plots you can download as PNG.
  • Statistical tables: printable z, t and chi-square tables with a lookup.
  • Guides: how to do the calculations by hand, in Excel or in Google Sheets.