Survey Sample Size Calculator
Calculate the ideal sample size needed for statistically significant survey results based on your population size, desired confidence level, and margin of error.
Parameters
Define your survey requirements.
Total number of people you could survey
How confident you want to be in results
Acceptable range of error (±)
Expected % choosing a particular answer (50% is most conservative)
Required Sample Size
Number of responses needed for statistical significance.
Required Sample Size
370
responses needed
Infinite Population
385
without finite correction
Surveys to Send
1,234
assuming 30% response rate
Quick Reference
Common sample sizes at 95% confidence, 5% margin.
Pop: 100
80
Pop: 500
217
Pop: 1,000
278
Pop: 10,000
370
Pop: 100,000+
384
Understanding Sample Size
Sample size determines how reliably your survey results represent the entire population. Larger samples increase accuracy but also cost more.
Key Concepts
- Confidence Level — Probability that results fall within the margin of error (95% is standard).
- Margin of Error — Range within which the true value lies (±5% is common).
- Population Size — Total people you could survey. Above ~10,000, it barely affects sample size.
Tips for Survey Success
- Plan for low response rates—send 3-5x your needed sample.
- Keep surveys short to improve completion rates.
- Send reminders to boost response rates.
- Offer incentives for participation.