📈 Business & Marketing
Conversion Lift Calculator
Calculate percentage lift between control and variant conversion rates. Free conversion lift calculator.
What This Calculator Tells You
Conversion lift measures how much better (or worse) a treatment performed than a control. It is the number teams quote after an A/B test, a landing page redesign or a holdout test for an ad campaign.
Enter the two conversion rates and the calculator returns both the relative lift (percentage change) and the absolute change in percentage points — two numbers that are often confused.
What to Enter
- Control conv. rate (%) — conversion rate of the baseline group, e.g. the current page or users who did not see an ad.
- Treatment conv. rate (%) — conversion rate of the new version or exposed group.
- Enter rates as percentages: 2.5 for 2.5%.
Worked Examples
1. A landing page redesign
Control converts at 2.5%, the new page at 3.1%.
- Relative lift +24%, absolute change +0.6 percentage points.
- On 100,000 monthly visitors that is about 600 extra conversions.
2. A checkout change that hurt
Control 12.0%, treatment 11.4%.
- −5% relative, −0.6 points.
3. A large base rate
Email open rate moves from 40% to 42%.
- +5% relative, +2 points — small in relative terms, but a big absolute gain on a large list.
How It’s Calculated
How to Read Your Result
- Relative lift is best for comparing tests on pages with different baselines.
- Absolute change is what turns into revenue: multiply it by traffic.
- Lift alone is not proof. Check significance with the A/B test calculator before you celebrate.
- Expect smaller lifts later. Early tests often show inflated lifts that shrink with more data.
Common Mistakes to Avoid
- Mixing up percent and percentage points. 2% → 3% is a 1-point increase but a 50% lift.
- Quoting lift without sample size or confidence.
- Comparing groups that were not randomly split. Before/after comparisons pick up seasonality.
- Reporting the best segment after slicing the data many ways.
When to Use This Calculator
- Report experiment results in a format stakeholders understand.
- Estimate extra conversions or revenue from a winning variant.
- Measure incremental impact of an ad campaign with a holdout group.
- Compare the size of wins across different tests.
Frequently Asked Questions
How is conversion lift calculated?
Relative lift = (treatment rate − control rate) ÷ control rate × 100. Absolute change = treatment rate − control rate.
What is a good conversion lift?
Most mature A/B tests produce single-digit relative lifts; 10%+ is a strong result. Huge lifts on small samples often regress.
What is incremental lift in advertising?
It compares conversions among people shown an ad with a randomly held-out group that was not, isolating the ad's true effect.
Is a negative lift useful?
Yes. It tells you the change hurt performance and should not ship — that is a valuable result.
Do you store the values I enter?
No. All calculations happen in your browser. Your data never leaves your device.
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