Description: Today tourism is one of the leading sectors of the global and the regional economy. But along with the positive impact of tourism on the country's economy, there are certain factors which are negative. The purpose of this article is to formulate and justify an approach to the calculation of quantitative assessment of the inbound tourism impact on the country's economy and its qualitative equivalent. To reach this goal, the application of the theory of fuzzy logic and fuzzy inference system was used. Fuzzy inference includes all the main components of the theory of fuzzy logic, such as linguistic variables, membership functions, meth-ods of fuzzy implication. As a method for the implementation of fuzzy inference the simplified fuzzy inference algorithm was cho-sen. As input parameters to carry out the calculation of the impact on the country's economy the number of international tourist arrivals to the country, the average receipts per arrival and the percentage of employment in the travel and tourism industry were chosen. To obtain the result, the necessary linguistic terms to estimate the input variables were determined; membership functions were constructed for all linguistic terms; a rule base (the set of if-then rules that define the relationships between the input and output of the system) was built; a firing strength of each rule on the base was obtained and the result was obtained by the centre of gravity method. Using this approach, a numerical experiment was carried out to quantitatively determine the in-bound tourism impact assessment on the economies of 6 countries as well as the qualitative equivalent of this assessment in ac-cordance with the verbal-numerical Harrington scale. This numerical experiment shows, that countries such as the USA, China and France have positive or even high positive impact on their economies, Poland and Bulgaria have low positive impact and Ukraine has negative inbound tourist impact on the country's economy.Using this approach with other input parameters, it is possible to perform an assessment (quantitative and qualitative) of any systems of a similar nature.
Keywords: fuzzy logic, linguistic variable, fuzzy inference system, inbound tourism, impact.