Sample Size Calculator

Calculate sample size for surveys and research studies, or determine margin of error for existing data

Calculate sample size for surveys and research studies, or determine margin of error for existing data.

Sample Size Calculator

Calculate the minimum sample size needed for statistical significance or determine the margin of error for your survey results.

Find Out The Sample Size

This calculator computes the minimum number of necessary samples to meet the desired statistical constraints.

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Use 50% if not sure

Leave blank if unlimited population size

Find Out the Margin of Error

This calculator gives out the margin of error or confidence interval of observation or survey.

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Leave blank if unlimited population size

About Sample Size and Margin of Error

Sample size and margin of error are fundamental concepts in statistics that help ensure the reliability and accuracy of survey results and research studies.

Key Concepts:

  • Sample Size: Number of observations needed for statistical significance
  • Margin of Error: Maximum difference between sample and population
  • Confidence Level: Probability that results are accurate
  • Population Proportion: Expected percentage with characteristic

Common Confidence Levels:

90%: Z-score = 1.645
95%: Z-score = 1.96 (most common)
99%: Z-score = 2.576
• Higher confidence = larger sample size needed

Applications:

  • • Market research surveys
  • • Political polling
  • • Medical studies
  • • Quality control
  • • Social science research
  • • Customer satisfaction surveys

Tips:

  • • Use 50% proportion when uncertain
  • • Larger sample = smaller margin of error
  • • Consider finite population correction for small populations
  • • Balance accuracy needs with practical constraints
  • • Higher confidence levels require more samples