Sample Size Calculator for Population Proportion
Calculate the required sample size for estimating a population proportion based on confidence level, estimated proportion, and margin of error.
Calculate the required sample size for estimating a population proportion based on confidence level, estimated proportion, and margin of error. Enter your Z-score (Z), Estimated Proportion (p), Margin of Error (E) to get an instant required sample size (n). Formula: round((z * z * p * (1 - p)) / (e * e), 0).
Required Sample Size (n)
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How It Works
How It Works
This calculator estimates how many respondents you need to accurately measure a population proportion. It uses your chosen confidence level (Z-score), expected proportion (p), and desired margin of error (E) to determine the minimum sample size required.
- The Z-score reflects your confidence level (e.g., 1.96 for 95% confidence).
- The estimated proportion (p) is your best guess of the population percentage.
- The margin of error (E) shows how precise you want your results to be.
- The formula calculates the minimum number of respondents needed.
- The result is rounded to the nearest whole number.
Understanding the Results
The result shows the minimum number of respondents required to achieve your desired confidence level and precision. A larger sample size increases accuracy but may require more time and resources.
- Higher confidence levels increase the required sample size.
- Smaller margins of error require larger samples.
- If you are unsure about p, using 0.5 gives a conservative (larger) estimate.
- The output is the number of respondents you should survey.
Disclaimer
This calculator provides estimates for informational purposes only. It is not professional advice. Verify results with a qualified professional. Disclaimer.