The article presents the consideration of grading scales used for education outcomes in different countries, describes likeness and differences of applied grading scales. Application of the European Credit Transfer and Accumulation System (ECTS) grading scale is investigated according of the analysis of scientific literature as well as cases of its mistaken application. The article provides a model for grades transfer from one scale into another, specifies the results of experimental testing of the introduced model, and analyzes cases of mistaken grades transfer.