In many applications, a Fuzzy Inference System is used to perform linguistic computation, but at the end of the inference process, a numerical value is needed. It does not mean that the system needs precision, but simply that a numerical value is required, most of the times because it will be used to control another system that needs the number. To obtain this numer, a defuzzification method is performed.

Several deffuzification methods were proposed, and they can be created as classes that implements this interface.