Pevlika Browser Apps

Sample Size Calculator

How many survey responses you need for a given margin of error.

Runs in your browser — nothing is uploaded
50% is the most conservative choice.

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How to use Sample Size Calculator

  1. Enter your values — the unit for each field is shown next to it.
  2. The result updates instantly as you type.
  3. Copy the results, or change inputs to compare scenarios.

Formula & assumptions

n₀ = z²·p(1 − p) / e²

n = n₀ / (1 + (n₀ − 1)/N)

Example: 95% confidence, ±5% margin → 385 responses for a large population.

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