How to measure Journal Impact Factor Quartile

The Journal Impact Factor quartile is the quotient of a journal’s rank in category (X) and the total number of journals in the category (Y), so that (X / Y) = Percentile Rank Z.

Q1: 0.0 < Z ≤ 0.25

Q2: 0.25 < Z ≤ 0.5

Q3: 0.5 < Z ≤ 0.75

Q4: 0.75 < Z