A/B Test Sample Size
Calculate A/B Test Sample Size instantly. Free online calculator with the exact formula, a worked example, and metric units. No signup required.
A/B Test Sample Size
Baseline conversion rate
MDE (rel.)
α
Sample per group
14,735
More about: A/B Test Sample Size
What it calculates
The “A/B Test Sample Size” calculator computes Sample per group from 3 parameters: baseline conversion rate, mde (rel.), α.
A core calculation for studying, engineering tasks, and checking solutions.
Example calculation
With parameters Baseline conversion rate = 0.1, MDE (rel.) = 0.1, α = 0.05 the result is 14,735 (p₁=0,1, p₂=0,11).
How to use
- Enter baseline conversion rate, mde (rel.) and α — each field above is adjustable with a slider.
- Sample per group is calculated automatically as you type.
- Check the worked example below to see the formula applied to real numbers.
- Copy the result or bookmark this calculator.
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FAQ
How is A/B Test Sample Size calculated?
The A/B Test Sample Size calculator computes Sample per group from baseline conversion rate, mde (rel.), α. Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the A/B Test Sample Size calculator free?
Yes. It is completely free, needs no signup, runs entirely in your browser, and sends no data to any server.
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