Sample Size Calculator – 99% confidence, 3% margin
Find required sample size for 99% confidence and 3% margin of error. Enter proportion or variability; we solve for n. For planning only.
Basic statistics
Enter numbers to compute.
How it works
We solve for n given confidence level and margin of error. Result depends on assumed proportion or SD.
When to use it
Use when designing surveys or A/B tests.
Frequently asked questions
What if I don't know proportion?
Use 0.5 for maximum required n.
For finite population?
We can apply finite population correction if you enter population size.