Free tool
Sample size calculator
Sample size is how many completed responses you need for results you can reasonably rely on.
Responses needed
385
Assumptions: simple random sampling and the standard formula n = z² · p(1−p) / e², with a finite population correction when you enter a population size.
Use 50% for expected proportion if you are unsure; it gives the most cautious (largest) result. This is an estimate, not a substitute for study design advice.
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