What does the p-value tell me?

If the p-value is less than your significance level (commonly 0.05), you reject the null hypothesis and conclude that at least one group mean is significantly different from the others. A large p-value means the observed differences could be due to random variation.

How many groups and values can I use?

You can enter between 2 and 8 groups. Each group must have at least 2 values. There is no strict upper limit on values per group, but very large datasets may slow down the browser.

Does one-way ANOVA tell me which groups differ?

No. ANOVA only tells you that at least one group is different. To find out which specific pairs differ, you need a post-hoc test such as Tukey's HSD or Bonferroni correction.

What are the assumptions of one-way ANOVA?

The main assumptions are: (1) independence of observations within and across groups, (2) normality of residuals within each group, and (3) homogeneity of variances (equal variance across groups). Violations may require alternative tests such as Welch's ANOVA or Kruskal-Wallis.

How is the p-value computed here?

The p-value is approximated using the regularized incomplete beta function to evaluate the F-distribution CDF, which is standard for ANOVA p-value computation. Results match those from R, Excel, and SPSS for typical sample sizes.

Is my data sent to any server?

No. All calculations run entirely in your browser using JavaScript. Your data never leaves your device.

One-Way ANOVA Calculator

Enter up to 8 groups of data and instantly compute the F-statistic, p-value, and ANOVA table to test whether group means differ significantly.

Enter Group Data

One value per line or comma-separated. Min 2 groups, max 8.

Enter group data and click Calculate ANOVA to see results.

F-statistic

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p-value

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df Between

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df Within

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ANOVA Table

Source	SS	df	MS	F	p-value

Group Summary

Group	n	Mean	Std Dev	Min	Max

Summary

The One-Way ANOVA Calculator performs a one-way analysis of variance on up to 8 independent groups. It computes the between-group and within-group sum of squares, degrees of freedom, mean squares, the F-statistic, and an approximate p-value — all in your browser with no data ever leaving your device. Use it to determine whether at least one group mean is statistically different from the others.

How it works

Enter your data for each group, one value per line or comma-separated.
Add up to 8 groups using the "Add Group" button; remove unwanted ones with the X button.
Click "Calculate ANOVA" to compute the ANOVA table.
The tool displays SS (Between), SS (Within), degrees of freedom, mean squares, F-statistic, and p-value.
Compare the p-value to your chosen significance level (e.g. 0.05) to decide whether to reject the null hypothesis.
Review the group summary table for individual means, variances, and counts.

Use cases

Compare test scores across three or more teaching methods.
Analyze crop yields under different fertilizer treatments.
Test whether customer satisfaction scores differ across product versions.
Evaluate machine performance across multiple production lines.
Check if response times differ between software algorithm variants.
Assess blood pressure differences among multiple treatment groups in a clinical study.
Compare employee productivity scores across different departments.
Validate measurement consistency across several lab instruments.

Frequently Asked Questions

Last updated: 2026-06-13 · Reviewed by Nham Vu