P-Value Calculator
Calculate the p-value from a z-score, t-statistic, or chi-square statistic.
Determine statistical significance for your hypothesis test.
P-Value Results
What is a P-Value?
The p-value is the probability of getting a result at least as extreme as the one observed, assuming the null hypothesis is true.
Common significance levels:
- p < 0.05 — statistically significant (most common threshold)
- p < 0.01 — highly significant
- p < 0.001 — very highly significant
Test types:
- One-tailed (left): Tests if the value is significantly less than expected
- One-tailed (right): Tests if the value is significantly greater than expected
- Two-tailed: Tests if the value is significantly different in either direction
Important: A small p-value does not prove your hypothesis is true. It only says the observed result would be unlikely if the null hypothesis were true.