Conversion Uplift Calculator
Compare a control and variant conversion rate to get the absolute and relative uplift — the two lift numbers people constantly confuse.
How it works
Absolute uplift = variant − control (percentage points) · Relative uplift = (variant − control) ÷ control × 100
Uplift comes in two flavours that are easy to mix up. Absolute uplift is the plain difference in percentage points; relative uplift expresses that gap as a share of the starting rate. Going from 5% to 6.5% is only a 1.5-point absolute change but a 30% relative uplift — headlines usually quote the relative figure because it sounds larger, so always check which one is meant before celebrating.
Worked example
Control converts at 5%, variant at 6.5%. Absolute uplift = 6.5 − 5 = 1.5 percentage points. Relative uplift = 1.5 ÷ 5 × 100 = 30%. Same result, two very different-sounding numbers.
Frequently asked questions
Which uplift number should I report?
Report both, and label them. Relative uplift ("+30%") communicates impact, while absolute uplift ("+1.5 points") communicates the real size of the move. Quoting only the relative figure on a tiny base can be misleading.
Does a positive uplift mean the test won?
Not on its own. A raw uplift ignores sample size and noise — pair it with an A/B significance test to confirm the difference is unlikely to be chance before acting on it.
What if the control rate is zero?
Relative uplift divides by the control rate, so it is undefined when the control is 0%. In that case only the absolute change (in percentage points) is meaningful.
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This calculator is for educational purposes. Double-check important results before acting on them.