One-Way ANOVA Calculator (+ Tukey HSD)
Run a complete one-way analysis of variance in the browser — no SPSS licence needed. Paste each group on its own line and get the full ANOVA table (SS, df, MS, F, p), effect sizes (η², ω², Cohen's f) and, unlike most free calculators, Tukey HSD post-hoc comparisons with adjusted p-values and simultaneous 95% confidence intervals so you know exactly which groups differ. Levene's test for homogeneity of variances and per-group Shapiro-Wilk normality checks run automatically, with plain-language warnings. Every number is verified against R's aov() and TukeyHSD() to at least six significant digits.
AI Report
Let AI interpret your results: a downloadable Word document in APA 7 / business report format.
Frequently asked questions
How do I report one-way ANOVA results in APA 7 format?
Report F with both degrees of freedom, the p-value and an effect size, e.g.: "The effect of group on score was significant, F(2, 21) = 38.72, p < .001, η² = .79. Tukey HSD comparisons showed that Group 3 scored higher than both other groups (p < .01)." The AI Report generates the full APA paragraph and table.
What is the Tukey HSD test and when do I need it?
A significant ANOVA F only tells you that at least one group differs — not which one. Tukey's Honestly Significant Difference test compares every pair of groups while keeping the overall error rate at 5%, which is why its adjusted p-values are the standard follow-up to a significant one-way ANOVA.
What is the difference between eta squared and omega squared?
Both estimate the share of total variance explained by the group factor. Eta squared (η²) is simpler but slightly optimistic in small samples; omega squared (ω²) corrects this bias and is the value many journals now prefer.
Can I use ANOVA with unequal group sizes?
Yes — one-way ANOVA and this calculator handle unequal n without problems (Tukey comparisons use the Tukey-Kramer correction). Just make sure each group still has at least two observations, and check the Levene warning for variance differences.