ANOVA Calculator
One-way ANOVA across any number of groups with F, p, and eta-squared.
About this tool
Enter groups separated by semicolons with values separated by commas. The one-way ANOVA reports F, degrees of freedom, p, eta squared, group means and the grand mean.
How to use
How it works
ANOVA compares the variation between group means with the variation within groups. A large F means the means differ more than chance within-group scatter would suggest. It tells you that at least one group differs, not which; follow up with a post-hoc test. Eta squared is the share of variance explained by group.
F = MS_between ÷ MS_within η² = SS_between ÷ SS_total
Worked example
Two groups, hand-checkable
- Input
- 4,5,6;7,8,9
- Output
- F(1, 4) = 13.50, p = .021, η² = .77
- Walkthrough
- Means 5 and 8, grand mean 6.5. SS_between = 3 × 1.5² × 2 = 13.5; SS_within = 2 + 2 = 4, so MS_within = 1 and F = 13.5. η² = 13.5 ÷ 17.5 =.77.
Limitations
- One-way (one factor) only.
- Assumes equal variances and roughly normal groups; it does not run post-hoc comparisons.
Questions
What do the two df in F(2, 12) mean?
What F do three groups of five scores give?
Does a significant ANOVA tell me which group differs?
Features
- Means and eta squared
- Any number of groups
- Runs in your browser
Related resources
Guides and videos from around the web—opens on YouTube or the publisher’s site.
Finding mean, median, and mode
Khan Academy
Baseline summary stats for coursework checkoffs.
Watch on YouTubeHypothesis testing and p-values
StatQuest with Josh Starmer
Intuition for t/z/χ² decision rules.
Watch on YouTube
- Statistics and probability
Khan Academy
Full intro stats path next to hub calculators.
- Data Index
Math is Fun
Plain-language stats primers for table lookups.