Sample Size Calculator
Calculate how many survey responses you need to achieve statistically reliable results.
Calculate Required Sample Size
Quick Reference: Sample Sizes
Common sample sizes for different population sizes at 95% confidence, ±5% margin of error:
| Population | Sample Needed | % of Pop. |
|---|---|---|
| 100 | 80 | 80% |
| 500 | 218 | 44% |
| 1,000 | 278 | 28% |
| 5,000 | 357 | 7% |
| 10,000 | 370 | 4% |
| 100,000 | 383 | 0.4% |
| 1,000,000+ | 385 | <0.1% |
What is Sample Size?
Sample size is the number of completed survey responses you need to make reliable conclusions about your entire population.
Too few responses = unreliable data. Too many = wasted resources. This calculator finds the sweet spot.
Key Concepts
How much your results might differ from the true value. ±5% means if 60% say "yes", the true value is likely 55-65%.
How certain you want to be. 95% means if you ran the survey 100 times, 95 would fall within the margin of error.
The total group you're studying. Larger populations don't need proportionally larger samples.
Pro Tips
- 💡 Plan for 2-3x your target sample to account for low response rates
- 💡 For subgroup analysis, each subgroup needs its own adequate sample
- 💡 ±5% at 95% confidence is the standard for most business surveys
Related Tool
Already collected responses? Calculate your actual margin of error:
Margin of Error Calculator →