Online Tool Store
ANOVA Calculator
ANOVA Calculator tells you that the groups differ; a post-hoc test is what tells you which ones. Runs entirely in your browser with no upload and no sign-up.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Math & Science
ANOVA Calculator
Frontend preview — no upload or external service.
ANOVA table
F(2, 9) = 18.4, p = 0.0007, eta squared 0.80. The groups differ, and 80% of the variance is between groups — but ANOVA does not say which pair differs.
How the ANOVA Calculator works
- Enter each group's values on its own line; groups need not be the same size.
- Read the F statistic and p value, then the effect size, which tells you how large the difference is rather than whether it exists.
- If the result is significant, run a post-hoc test to find which groups differ — ANOVA only says that at least one does.
The method
ANOVA compares variance between group means against variance within groups.
F = variance between groups / variance within groups
A large F means the group means are spread wider than the noise within each group would explain.
FAQ
What does a significant ANOVA tell me?
That at least one group mean differs from at least one other. It does not say which, or how many. A post-hoc test such as Tukey's is what identifies the pairs, with correction for multiple comparisons.
Why not run several t-tests instead?
Because each test carries its own false positive risk, and running many inflates the overall chance of a spurious result. ANOVA tests all groups at once, controlling that risk.
What assumptions does ANOVA make?
Independent observations, roughly normal residuals, and similar variance across groups. It tolerates mild violations, but very unequal variances or group sizes need Welch's ANOVA or a non-parametric alternative.
How we compare
| Feature | Online Tool Store | A graphing calculator | A stats package |
|---|---|---|---|
| Effect size reported | ✓ | ✗ | ✓ |
| Assumption notes | ✓ | ✗ | Sometimes |
| Nothing uploaded | ✓ | ✓ | ✗ |
| No install | ✓ | ✗ | ✓ |
ANOVA Calculator tells you that the groups differ; a post-hoc test is what tells you which ones.