The required completed sample is about 370 responses.
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Survey Sample Size Calculator
Plan the number of completed responses needed for a proportion estimate under a simple random-sample model.
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No account. Formula and assumptions are shown below.
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Formula & disclaimer
Initial Sample = zΒ² Γ p Γ (1βp) Γ· eΒ²; apply finite population correction when a population size is entered
View assumptionsFormula reviewCalcs at Hand Editorial TeamVerified 1 September 2026 Β· automated checks included
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How to read this result
Three useful checks, kept deliberately short.
95% confidence, 5% margin of error, 50% expected proportion and population of 10,000: Use z = 1.96 Β· Calculate the large-population requirement Β· Apply the finite population correction.
Non-response, clustering, weighting and selection bias may require a larger invited sample or a different design.
Formula and assumptions
Initial Sample = zΒ² Γ p Γ (1βp) Γ· eΒ²; apply finite population correction when a population size is enteredA 50% expected proportion gives the most conservative sample size when the likely proportion is unknown.
Keep in mind: This is a simple random-sample planning estimate and does not correct survey bias or complex sampling design.
Produced byCalcs at Hand Editorial Team
Last formula check1 September 2026
Review methodKnown examples + boundary cases
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