Test Duration Calculator
Centered A/B test duration calculator with three sliders feeding a big day count, a six week calendar grid, and a plain verdict line.
Centered A/B test duration calculator with three sliders feeding a big day count, a six week calendar grid, and a plain verdict line.
Search blocks by description or jump to a page.
The source for every Marketing block is included with Basic and Pro. Pick a plan to copy the code.
Already purchased? Log in
Test Duration Calculator turns three sliders into an honest calendar. Daily visitors, baseline conversion, and the lift you want to detect feed a sample size formula, and the result panel prints the days a test needs, paints them onto a six week grid one square per day, and rounds up to full weeks so weekday swings cancel out. A plain verdict tells the visitor whether the wait is normal or the lift is simply too small.
A client component on the ui Slider with plain useState, the math runs at 95% confidence and 80% power with the formula spelled out in the footnote. Results round up to whole days and whole weeks because a duration quoted to the hour reads as false precision on a page like this.
Reach for this block on an experimentation or CRO product page where the value is running tests properly rather than fast. Calling a winner early is the most expensive habit in the discipline, and a calendar the visitor built from their own traffic makes the real wait concrete before you ask them to trust your tooling with it.
A natural flow around it on a Marketing Pro page:
Before
After
One strong use is A/B test duration in days. Other experiment framings:
Tip: keep the confidence and power in the footnote, a duration with no assumptions is a guess wearing a number.