Representative Sample Online Calculator

Need to know how many people to poll? Simply input your total population size, desired confidence level, and acceptable margin of error, and let us help you determine the ideal sample size for your study.

Not sure how many people you need to poll? Not even sure where to begin? Let’s try to answer both. First this is a handy tool designed to aid in the planning and execution of statistically sound studies. In statistics, a representative sample is a subset of a statistical population that accurately reflects the members of the entire population. It’s crucial in any statistical analysis or study as it provides insights into the larger group from which they’re drawn – the population. The objective is to derive meaningful conclusions from the sample that can be generalized to the population. This underscores all social science and many natural sciences. If this premise is flawed entire fields (sociology, political science, nutrition sciences..etc) are likely flawed. More about this particular calculator. 

This calculator is particularly useful for those conducting surveys or research studies where obtaining data from the entire population is not practical. Fields like market research, sociology, public health, and political polling often utilize representative sampling. For instance, a market researcher interested in the preferences of smartphone users worldwide could use this tool to determine how many users need to be surveyed to confidently generalize the results to the entire population of smartphone users. Similarly, in epidemiology, representative samples can be used to estimate disease prevalence in a larger population based on a smaller sampled group. Remember, the key to representative sampling is randomness and size, ensuring each member of the population has an equal chance of being selected and the sample size is large enough to confidently reflect the population.

How to calculate a Representative Sample


Enter Population Size

The population size is the total number of individuals in the group you want to study. In the text input field labeled "Enter population size", input the size of the population from which you want to draw a sample. For example, if you're studying the preferences of smartphone users worldwide, the population size could be the total number of smartphone users around the globe.


Enter Confidence Level

The confidence level indicates the probability that the value of a parameter falls within a specified range of values. It's expressed as a percentage (90%, 95%, 99%), and a higher confidence level means a smaller chance of ending up with a result that doesn’t reflect the actual population. In the field labeled "Enter confidence level (90, 95, 99)", input the desired confidence level for your study. For instance, if you want to be 95% confident that your sample accurately reflects the population, you would input "95".


Enter Margin of Error

The margin of error indicates the amount of random sampling error in a survey's results. It's also expressed as a percentage and determines the range that the true population parameter will fall. For example, a margin of error of 5% means the real value could be 5% higher or lower than the stated result. In the input field labeled "Enter margin of error (in %)", input the acceptable margin of error for your study. If you can accept a potential error of 5% in either direction, you would input "5".


Find that sample!