Mann–Whitney U test calculator
Paste two independent samples. The calculator assigns pooled ranks and tests whether values in one group tend to be larger.
Pooled ranks
| Value | Group | Rank |
|---|---|---|
| Fill in the fields above — the result is computed on this page. | ||
How do I use this page?
- Paste independent samples A and B.
- Choose a one- or two-sided alternative.
- Read U, z and the p-value.
What this page does not do: For very small samples an exact U distribution may produce a different p-value. Observations must be independent between groups.
Further reading
Theory — what is the Mann–Whitney U test?
The Mann–Whitney U test is a nonparametric comparison of two independent samples that does not require a normal distribution. All observations from both groups receive pooled ranks, and the U statistic describes how these ranks are arranged between the groups. The calculator applies a correction for tied ranks together with an approximation, keeping the result reliable even with repeated values. The shape of the compared distributions still affects how the detected difference should be interpreted.
Frequently asked questions
Must the data be normal?
May sample sizes differ?
See also
A/B test calculator
Compare two proportions in an A/B test. Calculate conversion rates, difference, uplift, z score, p value and c
A/B test planning — sample size, MDE and duration
Plan a two-proportion experiment, estimate detectable effect and traffic duration.
ACF and PACF autocorrelation calculator
Calculate ACF and PACF across time-series lags. Review the chart, reference bounds and coefficient table.