A/B Testing Screen Resolution Calculator FAQ
Answers to common questions about estimating A/B test traffic and duration for screen-resolution and viewport segments.
Use these answers to understand what a screen-resolution A/B testing estimate includes, which inputs matter, and why traffic planning differs from statistical test evaluation.
General calculator questions
Basic questions about the purpose and use of the calculator.
What does the A/B Testing Screen Resolution Calculator do?
It estimates daily traffic from a selected screen-resolution segment, traffic per variation, total required segment traffic, expected duration, and expected conversions per variation.
Who can use this calculator?
It is useful for experiment planning when a layout, interface, or experience is intended for a particular resolution or viewport segment.
Does the calculator test the design itself?
No. It only estimates traffic availability and timing. It does not evaluate design quality or determine which variation performs better.
Can I enter a viewport size instead of screen resolution?
Yes, if the segment is defined that way in your analytics or experimentation platform. Label the input clearly so the estimate matches the data source.
Traffic and duration calculations
Questions about how the traffic and time estimates are produced.
How is screen-resolution segment traffic calculated?
The calculator multiplies total daily eligible visitors by the percentage share of visitors in the selected segment.
How is traffic split between variations?
The estimate divides segment traffic equally by the number of variations, including the control.
Why is the duration rounded up?
A partial day may not provide the full required visitor target, so the estimate rounds up to the next whole calendar day.
What is total required segment traffic?
It is the visitor target for one variation multiplied by the total number of variations.
Can I use unequal traffic allocation?
This calculator assumes equal allocation. Unequal allocation changes the daily traffic and time needed for each variation.
Visitor targets and conversion events
Questions about choosing inputs and interpreting conversion estimates.
How many visitors per variation should I enter?
Use a target based on the experiment's planned analysis, baseline conversion rate, and smallest effect of interest. The calculator does not set that target.
What does expected conversions per variation mean?
It is the target visitor count multiplied by the expected conversion rate. It is an estimate of events, not a guaranteed result.
Why might 1,000 visitors per variation be too few?
At low conversion rates, 1,000 visitors can produce very few conversion events. The required sample depends on the metric and the effect being evaluated.
Should I use the overall site conversion rate?
Use the best available estimate for the selected segment and metric. Segment behavior may differ from the overall site average.
Accuracy and data definitions
Questions about assumptions, data quality, and interpretation.
Is screen resolution the same as viewport size?
Not necessarily. Screen resolution, viewport dimensions, CSS pixels, device pixel ratio, and responsive breakpoints can describe different things.
Why might actual segment traffic differ from the estimate?
Traffic shares may change because of seasonality, campaigns, weekday patterns, device mix, consent rules, or differences between reporting tools.
Does this calculator account for repeat visitors?
No. It treats each eligible visitor as one observation and does not adjust for identity resolution or repeat exposure.
Does reaching the estimated duration mean the test is complete?
Not by itself. The estimate only shows when a visitor target may be reached; experiment quality and the planned statistical method also matter.
Using the result in experiment planning
Questions about practical uses of the traffic estimate.
When is segment-only testing useful?
It can be useful when the proposed change is specifically relevant to that segment, such as a responsive layout or screen-size-specific interaction.
What if the selected resolution has very little traffic?
The estimate may show a long duration. You may need to reconsider the segmentation definition, test scope, or the feasibility of collecting enough observations.
Should I include the control in the variation count?
Yes. The control receives traffic and needs to be included in the total number of versions sharing the segment.
What does the A/B Testing Screen Resolution Calculator do?
It estimates daily traffic from a selected screen-resolution segment, traffic per variation, total required segment traffic, expected duration, and expected conversions per variation.
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