Minimum Sample Size Calculator
Estimate the sample size needed for a survey from confidence, margin and proportion.
Compare Your Options And Get Clear Answers
Estimate the sample size needed for a survey from confidence, margin and proportion.
Minimum Sample Size Estimator
Enter your numbers below for an instant estimate.
How It Works
Key concepts behind this calculator
Enter Values
Fill in each field with your own numbers.
Calculate
Results update as you change the inputs.
Review
Read the breakdown and the explanation.
Adjust
Change values to compare scenarios.
Minimum Quick Guide
Typical values for reference.
| Z score (1.96 for 95%) | Margin of error (%) | Expected proportion (%) | Required sample |
|---|---|---|---|
| 1.96 | 5 | 50 | 385 people |
| 1.96 | 3 | 50 | 1,068 people |
| 2.576 | 5 | 50 | 664 people |
| 1.96 | 5 | 20 | 246 people |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Minimum Sample Size Calculator FAQ
Answers to common questions about this calculator.
It uses the formula shown with your inputs. Real conditions vary, so treat it as a guide.
Use 50 percent when unsure of proportion.
It is an estimate based on the inputs you enter. Check real quotes, labels or official guidance for important decisions.
Yes. Replace each input with your own figures and the result updates instantly.