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Label The 'Sample Size Calculator' aims to assist users who are not experts in statistics to be able to estimate a suitable sample size when collecting data from a process. The calculator deals with continuous and discrete data and it is designed to be as practical and intuitive as possible returning a straight answer. The tool can assist users to make decisions such as:

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Example 1: You want to make inferences about the average travel time from home to office. How many values you need to get?.

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Example 2: As a supervisor of an administrative process, you have developed a different method to perform a task. Now you wish to confirm statistically if the average time of the new method is better. How many samples you need to collect to further perform a statistical study?
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Example 3: A social worker wants to know the sample size (n) needed to determine the proportion of the population served by a given hospital.

Label Please just follow the steps below.


Data Type
Confidence Level
Size of preliminary sample (optional)
Standard Deviation of preliminary sample
Precision (optional)



Label After collecting your sample values, you will have a better estimation of the standard deviation, so you'd better return to the tool in oder to confirm if your sample size is suitable.

Label Be aware that leaving the optional fields blank might make the tool to suggest a sample bigger than necessary. The better the information provided for the standard deviation (in case of continuous data) or probability of an occurrence (in case of discrete data) the more accurate is the result. If you dont have such information you can get a preliminary sample (let's say at least 10 values) or estimate it from an already existent study for a case similar to yours.


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