P-Value Calculator
Choose the distribution that produced your test statistic, enter the statistic and degrees of freedom when required, and calculate the corresponding tail probability.
Match the probability distribution and tail before reading the number
A p-value is a tail area under the null distribution of a test statistic. Lynara keeps z, Student t and chi-square as separate modes because the same numerical statistic can map to a different probability under a different distribution.
The calculator deliberately does not turn one threshold into an automatic “significant / not significant” verdict. Pair the p-value with the study design, effect size, interval estimates and the decision rule required by your course or analysis.
Privacy: calculator inputs are processed in your browser; Lynara does not need to upload these values to calculate the result.
Formula
z/t: p = matching normal or Student t tail area; chi-square: p = upper-tail area
Example
For z = 1.96, the two-tailed p-value is about 0.0500; for chi-square = 3.841 with 1 df, the upper-tail p-value is about 0.0500.
Useful for
- Convert a reported z statistic to a p-value
- Convert a t statistic and degrees of freedom to a p-value
- Convert a chi-square statistic to its upper-tail p-value
Questions
Which tail should I choose for z or t?
Use the alternative hypothesis specified before inspecting the result. Two-tailed counts extreme results in either direction; left and right tails are directional.
Why is chi-square upper-tailed here?
Pearson chi-square statistics are nonnegative and common goodness-of-fit or independence tests use the upper tail for larger departures from the null model.