Free statistics calculators, every step shown

Test a Hypothesis

Use these calculators when you need to know whether a difference between groups, or a link between two categories, is larger than chance would explain. Start with the test chooser if you are not sure which test fits your data; the t, z, ANOVA and chi-square calculators then return the test statistic and p-value, and the p-value and critical-value calculators convert a statistic you already have.

Tools in this group

  • One-Way ANOVA Calculator — Paste one column per group to get the ANOVA table, F and p-value, effect sizes and Tukey HSD comparisons of every pair.
  • Chi-Square Test Calculator — Paste a table of counts to test whether two categorical variables are independent: χ², p-value, expected counts and Cramér's V.
  • Chi-Square Goodness of Fit Calculator — Enter observed counts and the expected counts or ratio to test whether the data follow that distribution.
  • Critical Value Calculator — Choose z, t, chi-square or F, the significance level and the tail to get the critical value and the rejection region.
  • P-Value Calculator — Enter a z, t, chi-square or F statistic and the degrees of freedom to get the p-value, the critical value and whether the result is significant.
  • Paired T Test Calculator — Paste two matched columns (or the differences) to test whether the mean change differs from zero, with every step shown.
  • T Test Calculator — Paste one or two samples (or type means, SDs and sizes) to get the t statistic, p-value, confidence interval and effect size.
  • T Test vs Z Test — Enter a mean, SD and sample size to run a t test and a z test side by side and see which one applies to your data.
  • Two-Way ANOVA Calculator — Paste one observation per line (factor A, factor B, value) to get the two-way ANOVA table with the interaction and cell means.
  • What Statistical Test to Use? (Test Chooser) — Answer a few questions about your data and see which statistical test fits, why, and what the alternative is.
  • Z Test Calculator — Choose a mean or proportion z test, enter your numbers and get z, the p-value, the decision at α and a confidence interval.