sample size calculator
sample size calculator

Sample Size Calculator

Study Parameters

Population
Proportion

Sample Size Formulas

For known population:
n = N / (1 + N(e²))
For proportions:
n = (Z² × p × (1-p)) / e²
Where:
n = sample size, N = population size
Z = Z-score (1.96 for 95% CI)
p = expected proportion, e = margin of error

Calculation Results

Required Sample Size

278

95% confidence level with ±5% margin of error

Sample Size Examples

National survey (100M population)
384
University study (10,000 students)
370
Customer survey (1,000 customers)
278
Clinical trial (rare disease, 100 cases)
80

Sample Size Calculator

Accurately determine how many observations or participants you need in a survey or experiment to achieve statistically significant results.

The Sample Size Calculator helps researchers, students, and professionals in determining the number of samples required to make reliable inferences about a population. This tool is crucial for ensuring valid, confident decision-making without over- or under-sampling.

Key Features

How to Use the Calculator

  1. Enter your desired confidence level (e.g., 95%)
  2. Specify your margin of error (e.g., 5%)
  3. Input estimated population proportion (e.g., 0.5 for 50%)
  4. Provide the total population size if known (optional)
  5. Click "Calculate" to see the recommended sample size

Why Use a Sample Size Calculator?

Popular Use Cases

Conclusion

The Sample Size Calculator is a vital tool in any statistical analysis process. By helping you determine the right number of participants or data points, it ensures your results are accurate, valid, and meaningful. Use it to confidently conduct research and make informed decisions.