Poll Margin Calculator
Estimate simple random-sample uncertainty for a reported proportion.
What this tool is for
How to use it
This calculator estimates the familiar 95% sampling margin for one proportion under a simple-random-sample model. Enter the reported percentage and sample size to see the approximate uncertainty created by sampling alone.
What it does not prove
The output does not include weighting, design effects, nonresponse, likely-voter screens, question wording or model choices. Real polling error can therefore be larger than the displayed number, and differences between two candidates require their joint uncertainty rather than two isolated margins.
When to escalate
Use the estimate to challenge false precision, not to declare a poll “inside” or “outside” an absolute truth band. Compare field dates, population, methodology and trends across multiple surveys before drawing campaign conclusions.