Conversion & UX
A/B Test Duration Calculator
Calculate required test duration based on traffic and conversion goals.
Always run tests for at least 1-2 full business cycles (weeks). Avoid stopping tests early.
What is the A/B Test Duration Calculator?
Calculate how long to run A/B tests based on traffic, baseline conversion rate, and minimum detectable effect.
The A/B Test Duration Calculator tells you exactly how many days to run your experiment for statistically valid results. Stopping tests too early leads to false positives - you'll think a variant won when it actually didn't. Running too long wastes time and traffic. Enter your daily visitors, current conversion rate, and the minimum improvement you want to detect, and this tool calculates the required sample size and test duration with 95% statistical significance.
Key Benefits
Statistical Validity
Ensure your test results are real, not random noise.
Prevent False Positives
Stop early stopping that leads to wrong decisions.
Resource Planning
Know upfront how long experiments will take to conclude.
Minimum Detectable Effect
Understand the smallest improvement your test can reliably detect.
How to Use This Tool
Enter your average daily unique visitors to the test page
Input your current (baseline) conversion rate as a percentage
Set the minimum detectable effect - the smallest lift you care about
Choose your statistical significance level (default 95%)
Review the required sample size and estimated test duration
Common Use Cases
- CRO specialists planning landing page experiments
- Product managers testing new feature variants
- E-commerce teams running pricing and CTA tests
- Marketing teams A/B testing email and ad creative
- Growth engineers setting up experimentation frameworks
Pro Tips
- Run tests for at least 2 full business cycles (typically 2 weeks) to capture variance
- Smaller MDE requires more traffic - be realistic about detectable improvements
- Don't peek at results and stop early - commit to the calculated duration
- Account for weekday vs weekend traffic patterns in your timeline
Who Uses This Tool
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Try itFrequently Asked Questions
What is the A/B Test Duration Calculator?+
The A/B Test Duration Calculator is a free online tool that helps you calculate required test duration based on traffic and conversion goals. No signup or download required.
Is the A/B Test Duration Calculator free?+
Yes, completely free with unlimited usage. No account needed.
How accurate is this tool?+
Our A/B Test Duration Calculator uses industry-standard algorithms and best practices to deliver reliable results for SEO professionals and marketers.
Can I use this tool on mobile?+
Yes, the A/B Test Duration Calculator is fully responsive and works on all devices including smartphones, tablets, and desktops.
Do you store my data?+
No. All processing happens in your browser. We never store, transmit, or share any content you input into our tools.