A/B Test Significance Calculator

How to Run A/B Tests That Matter

A/B testing is the backbone of data-driven marketing. But too many marketers call winners too early or test things that don't matter. Here's how to do it right.

A/B Testing Best Practices

• Wait for significance: 95% confidence is the standard. Below that, you're guessing.
• Test one thing at a time: Change only one variable so you know what caused the difference.
• Run tests for full weeks: Behavior varies by day of week. Don't stop mid-week.
• Calculate sample size first: Know how many visitors/emails you need before starting.
• Document everything: Track what you tested, when, and the results for future reference.

What to A/B Test in Email Marketing

• Subject lines: Highest impact, easiest to test
• Send times: Morning vs afternoon, weekday vs weekend
• CTAs: Button text, color, placement
• From name: Company name vs person's name
• Email length: Short and punchy vs detailed and informative