Free Tool

Statistical Significance Calculator

Did your variant actually win, or was it random noise? Paste your control and variant numbers — get a clear confidence level and p-value in seconds.

Control Group

Variant Group

Statistical Significance

Enter your test results and click Calculate to see statistical significance

Understanding Statistical Significance

What is Statistical Significance?

Statistical significance tells you whether the difference between your control and variant is likely due to the changes you made, or just random chance. A 95% confidence level means there's only a 5% chance the results are due to chance.

P-Value Explained

The p-value represents the probability that your results occurred by chance. A p-value less than 0.05 (5%) is typically considered statistically significant, meaning you can be 95% confident your results are real.

Common Questions

What confidence level should I use?

95% confidence (p-value < 0.05) is the industry standard for A/B testing. This means there's only a 5% chance your results are due to random variation.

What if my test isn't significant?

If your test doesn't reach statistical significance, you need more data. Use our Sample Size Calculator to determine how many visitors you need for reliable results.

Can I stop a test early if it's significant?

Stopping tests early can lead to false positives. Always run tests for the full duration calculated by our Test Duration Calculator to ensure reliable results.

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Go beyond calculators

Get real-time significance, automatically.

Humblytics calculates statistical significance continuously as your test runs — no manual number crunching. See live confidence levels, get notified when a winner emerges, and let your agent explain the results.