Sessions to Conversions Calculator
How much traffic a test actually needs.
Conversions
1,104
67,966 sessions per variant to test
Detecting a 10% relative uplift needs roughly 67,966 sessions per variant. Low-traffic sites cannot detect small wins in reasonable time, which is why they should test bold changes rather than button colours.
How the Sessions to Conversions Calculator works
Detecting a small uplift needs far more traffic than most stores have. Low-traffic sites cannot resolve a 5% improvement in reasonable time, which means they should be testing bold changes rather than button colours.
Not financial advice. Marketplace fees change, and they vary by country, plan and seller status. Every rate here is an editable default, not a quoted price — check the platform's current fee schedule before you price a product against it. This is not tax or business advice.
Frequently asked questions
How much traffic does an A/B test need?
It depends on baseline conversion rate and the size of effect you want to detect. Smaller effects and lower baseline rates both require dramatically more traffic.
Why does a small effect need so much more traffic?
Because the required sample scales with the inverse square of the effect size. Detecting half the effect takes four times the traffic.
What if I do not have enough traffic?
Test bigger changes, test on higher-traffic pages, or accept lower confidence and treat results as directional. Running an underpowered test to significance is worse than not testing.
How long should a test run?
Until the planned sample is reached, and in whole weeks. Weekday and weekend behaviour differ enough that partial weeks bias the result.