This paper presents a detailed study about external quality evaluation of a web software product using fuzzy logic as tool, thus allowing to evaluate the responses generated from the considerations that it's take into account for this purpose, making the system will be consolidated as an evaluation tool, based on the parameters that end users look to them. Given the demands of end users and increased a greater amount of requirements against software products, it is necessary that the quality is embedded and implemented at different levels of the development process, therefore it's necessary to have with new methods of evaluations to allow to know responses from the findings of users. The methodology of the research process was selected quasi-experimental with application surveys that define characteristics and levels that each user needs and then translate these parameters into a software product, so you can compare its results with measurements of users. As a first step was proposed to develop a preliminary investigation whose objective at describing the problem, formulate the hypotheses to be tested and determine the size of the sample. In addition, we selected different sites and indicators to evaluate each of the surveys. To validate the methodology and the developed tool, we performed a statistical analysis of the data. This process showed that results obtained by system, compared to those defined by end user are very similar and therefore have not significant differences among them, being able to ensure that software evaluates the quality of Web systems effectively.