Sampling Calculator
Calculate the optimal sample size for your survey — fast, free, statistics-based.
Sample Size Calculator
Determine the ideal number of respondents for your survey.
Margin of Error Calculator
Find out how accurate your survey results are.
Population
A population is the entire group of people, events, or objects that the researcher wants to investigate. It represents all elements that are the target of statistical inference from survey results.
Sample
A sample is a subset of the population consisting of some selected representative members. Not all population elements become the sample — only a portion is systematically selected to be representative.
Required Parameters
To calculate sample size, you need to know:
- Population Size (N) — total number of your targets (customers, residents, employees, etc.).
- Margin of Error (E) — error tolerance. Smaller → more accurate, but requires more respondents.
- Confidence Level (Z) — certainty that the sample reflects the population (90%, 95%, or 99%).
- Proportion (p) — estimated population proportion. Use 0.5 if no prior data available.
Statistical Formulas
Z = z-score based on confidence level, p = proportion (default 0.5), E = margin of error in decimal.
Tips & Best Practices
- First determine the survey objective — rough opinion or serious analysis. Serious analysis needs high confidence & small margin of error.
- Match budget and time — larger sample = more expensive & longer.
- Small population? Use finite population correction for more realistic results.
- No prior proportion data? Use p = 0.5 — this gives a conservative result (safe minimum).
What is Sample Size Used For?
- Customer satisfaction surveys
- Market research & brand tracking
- Political candidate surveys
- Product testing
- Employee satisfaction surveys
- Public opinion studies
Need professional survey assistance?
Consult your research needs with the IJS team — fieldwork & data processing specialist across 34 provinces in Indonesia.
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