This calculator is used to find the confidence interval (or accuracy) of a proportion given a survey´s sample size and results, for a chosen confidence level.
How To Interpret The Results
For example, suppose you carried out a survey with 200 respondents. If 45% of respondents answered the question of interest in a particular way and your desired confidence level was 95%, the corresponding confidence interval would be ± 6.9%. That is to say that you can be 95% certain that the true population proportion falls within the range of 38.1% to 51.9%.