Sample size calculator

What margin of error can you accept?

5% is a common choice

%

What confidence level do you need?

Typical choices are 90%, 95%, or 99%

%

What is the population size?

If you don't know, use 20000

What is the response distribution?

The most conservative choice is 50%

%

Alternate scenarios

With a sample size of

Your margin of error would be

With a confidence level of

Your sample size would need to be