Sales & marketing
A/B conversion significance Calculator
Compare two conversion rates using a two-sided pooled proportions test. This free a/b conversion significance calculator shows the calculation and its assumptions so you can compare your own figures.
Your results
Compare two conversion rates using a two-sided pooled proportions test.
Calculated outcomes
- Conversion APercent
- 10%
- Conversion BPercent
- 13%
- Percentage Point Difference
- 3
- Z Score
- 2.1027
- Reliable Approximation
- Yes
Assumptions and estimates
- Two-sided pooled two-proportion z-test; significance is suppressed when either group has fewer than 10 conversions or 10 non-conversions. Requires random independent assignment and a preplanned test; repeated peeking and multiple comparisons inflate false positives.
- Method: z = conversion-rate difference ÷ pooled standard error. The two-tailed p-value uses the normal distribution.
- Requires random independent groups and at least 10 conversions and non-conversions per group. Plan the stopping rule before testing.
Useful next steps
- Use Compare options to test an alternative side by side.
- Copy, print or download a record of this calculation when you need one.
Reports open your email app addressed to s@s1.ie with the public page address only. Your inputs are never added.
How the a/b conversion significance calculation works
z = conversion-rate difference ÷ pooled standard error. The two-tailed p-value uses the normal distribution.
Requires random independent groups and at least 10 conversions and non-conversions per group. Plan the stopping rule before testing.
Using this calculator
- Enter your own figures in the labelled inputs. Keep the currencies, units and time periods consistent.
- Choose any applicable rate profile, pattern or assumption shown for this tool. Open additional inputs when relevant.
- Review relative lift percent and p value and statistically significant, then read the stated assumptions and eligibility conditions before using the result.
Worked example
This is a static example using illustrative inputs, not facts about you or today’s date. The displayed eligibility selections and assumptions apply only to this example.
See example inputs
- Group A visitors
- 1000
- Group A conversions
- 100
- Group B visitors
- 1000
- Group B conversions
- 130
- Confidence threshold (%)
- 95
- Relative Lift Percent
- 30%
- P Value
- 0.0355
- Statistically Significant
- Yes