Use this ANOVA calculator to perform one-way ANOVA and post hoc comparison tests. Use the classic F-test ANOVA when you can assume group variances are equal or Welch’s ANOVA when they are not equal. Enter your data in either Stacked (i.e., long format) or Unstacked (i.e., wide format). For stacked data, copy and paste and from spreadsheets and the rows will auto-expand to fit your dataset. Ensure that outcome data are in the first column and group information in the second. For unstacked data, you’ll need to specify the number of groups and paste each group’s data into separate boxes. Choose your ANOVA options  and click Analyze to generate the results. If you include the variable names in the header, they will appear in the results.

The ANOVA calculator output includes an analysis of variance (ANOVA) table, model summary, group mean information, and graphical output. You’ll see values for R-squared, adjusted R-squared, and P-value, helping you assess whether the differences between group means are statistically significant and how well the model explains the variability in your data. The ANOVA calculator uses your significance level selection to construct all confidence intervals. It also calculates Tukey’s HSD or the Games-Howell post hoc tests depending on your ANOVA method choice. Additional statistical guidance follows the ANOVA calculator. See all my Statistical Calculators!

ANOVA Calculator Guidance

One-way ANOVA determines whether the difference between groups means are statistically significant. To learn more about this analysis, read my article One-Way ANOVA Overview & Example. This calculator can perform both the Classic and Welch’s form of one-way ANOVA. Learn more about the differences and when to use each in Benefits of Welch’s ANOVA vs Classic One-Way ANOVA.

In the ANOVA calculator omnibus results, assess the p-value in the Analysis of Variance table to determine whether you can reject the null hypothesis and conclude that the group means are different.

If your group means differ, use the post hoc test results to identify pairs of group mean differences that are statistically significant. The ANOVA calculator performs Tukey’s HSD with the classic F-test ANOVA and uses the Games-Howell post hoc test with Welch’s ANOVA. In this calculator, both Tukey and Games-Howell post hoc tests use a Sidák approximation to compute simultaneous confidence intervals and adjusted p-values while controlling the familywise error rate.

For the post hoc tests, if the adjusted p-value for a pair of group means is less than your significance level, those groups are significantly different. Correspondingly, if the simultaneous CI for a mean difference excludes zero, those groups are significantly different.

Learn more in-depth about Using Post Hoc Tests with ANOVA.

Learn how to interpret the following results in the ANOVA calculator:

• R-squared, Adjusted R-squared, S (standard error of the regression) in the Model Summary table.
• How to Perform One-Way ANOVA in Excel.