The Apdex equation is used to calculate a score. ... The equation is (70+20/2)/100= 0.8. The 0.8 score falls between 0 and 1. An excellent score falls in 1.00-0.94, a good score ranks from 0.93-0.85, a fair score hits 0.84-0.70 and a poor one between 0.69 and 0.49.