Sample size calculator

Error marginThe error margin is the amount of error that can be tolerated by using a sample instead of a census. A lower error margin requires larger sample sizes.


5% is commonly used

%

Confidence levelThe confidence level refers to the amount of uncertitude that can be tolerated. For example, for this market research study we would like to obtain results that can be inferred for "95%" of the population. Higher confidence intervals require larger sample sizes.


Common options are 90%, 95%, or 99%

%

Population sizeIs the amount of potential respondents in the sample's universe. Sample sizes are not very affected when the population is very large.


If unknown, use 200000

ProportionIs the amount of respondents that will answer the questions in a predetermined way. Generally, this parameter is unknown and we use 50% in order to obtain the largest sample size.

What is the distribution of answers?
Leave this as 50%

%

Sample sizeThis is the minimum recommended sample size for your market research study.
The sample has been calculated based on the Normal distribution and it is assumed that your population's universe has over 30 elements.

Your recommended sample size is:

384
 

Alternate scenarios

Compare the following sample scenarios by changing the value in each column and obtaining either the desired error margin or sample size.

With a sample size of
Your error margin would be
9.80%
6.93%
5.65%
       
With a confidence level of % % %
Your sample size would be
271
384
662