Convert z, t, chi-square, F and correlation r test statistics into exact p-values, one- or two-tailed, and compare them with your significance level.
About this tool
Convert z, t, chi-square, F and r statistics into p-values.
How to use P-value Calculator
- Choose the test statistic you have.
- Enter its value and the degrees of freedom or sample size.
- Choose one or two tails and read the p-value.
Worked example
t = 2.1 with 24 degrees of freedom gives a two-tailed p-value of 0.046, significant at α = 0.05.
One-tailed or two-tailed?
Use two-tailed unless you decided before seeing the data that only one direction matters. A one-tailed p is half the two-tailed value.
Does p < 0.05 mean the effect is important?
No. It only suggests the data are unlikely under the null hypothesis. Check the effect size and confidence interval for importance.
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