Degrees of freedom calculator
Choose an analysis type. Only the fields required by the selected formula are used.
How do I use this page?
- Choose the analysis.
- Enter the fields used by its formula.
- Read df and the displayed substitution.
What this page does not do: This calculator covers common simple models. Regression, mixed models and complex experimental designs can use different definitions or approximations.
Further reading
Theory — what are degrees of freedom?
Degrees of freedom indicate how much independent information remains in the data after estimating parameters or imposing constraints. Their formula depends on the chosen statistical model, which is why the calculator shows only the fields needed for the selected analysis. For Welch's test the result can be a non-integer, because the Satterthwaite approximation depends on the variance and sample size of both compared groups. Such a non-integer result is correct and follows from the method itself, not from a calculation error.
Frequently asked questions
Why is Welch df not an integer?
Which df should I report for ANOVA?
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.