P-Value Calculator · Practical guide
Is 0.05 Statistically Significant?
The 0.05 convention, where it came from, and what it does and does not tell you.
At a glance
The Short Answer
By convention, p less than 0.05 is statistically significant — it means the observed result (or something more extreme) would occur by chance under the null hypothesis less than 5% of the time. A p of exactly 0.05 is a borderline case; the standard is strictly p < 0.05.
Interactive tool
P-Value Calculator
Enter your own values, then compare the result with the examples below.
P-Value Results
What 0.05 Does and Does Not Mean
It does not mean there is a 95% chance your hypothesis is true, nor a 5% chance the whole result is a fluke in the everyday sense. It is a probability statement about the data given the null hypothesis — a subtle but important distinction.
Borderline Examples
| Test Statistic | Two-Tailed p | Verdict at α = 0.05 |
|---|---|---|
| z = 1.95 | 0.051 | Not significant |
| z = 1.96 | 0.050 | Borderline |
| z = 2.00 | 0.046 | Significant |
Significant Is Not the Same as Important
With a large enough sample, a trivially small effect can produce p < 0.01. Pair the p-value with the effect size and a confidence interval before drawing practical conclusions. This calculator flags significance at α = 0.05 based on the two-tailed value.
Frequently Asked Questions
Is p = 0.049 significant but p = 0.051 not?
Under the strict convention, yes — which shows how arbitrary a hard cutoff is. Report the exact p-value and the effect size rather than leaning on which side of 0.05 you landed.
Where did the 0.05 threshold come from?
Statistician Ronald Fisher popularized it in the 1920s as a convenient rule of thumb. It was never meant as a bright line between truth and error.
Can a result be significant at 0.10 but not 0.05?
Yes — a p-value of 0.08 clears a 0.10 threshold but not 0.05. Some exploratory studies use alpha = 0.10, but confirmatory research almost always uses 0.05 or stricter.
What does the calculator's interpretation line use?
It compares the two-tailed p-value against alpha = 0.05 and reports whether the result is significant at that level.