A/B Test Calculator
Plan how many visitors you need before launching a test — and check whether the test you already ran is statistically significant.
Plan a test
Inputs
Your current control conversion rate.
Smallest lift you care about. 10–20% is typical for landing pages.
For a duration estimate. Combined across both variants.
Sample size needed
24,190visitors per variant
Total of 48,380 visitors across both groups. At 5,000 daily visitors that is roughly 10 days.
Two-tailed test for two proportions. Lower MDE = more visitors needed (relationship is quadratic). Run for full week-cycles to avoid weekday bias.
Try these next
Related tools you'll probably want
Built by
Ariful Islam
Founder · 8+ years in tracking
$200K+earned on Upwork
Top Rated Plus
4.9/5 · 300+ engagements
