Generally, most of the journals use these two figures (A) and (B) to calculate the Impact Factor. Let us calculate the Impact Factor for a particular journal for the year 2023.
Impact Factor(IF-2023) = A/B
A -> The number of times that all items published in that journal in 2021 and 2022 were cited by indexed publications during 2023.
B -> The total number of “citable items” published by that journal in 2021 and 2022.
For Example,
A = 1298 (Number of times that all items published in that journal in 2021 and 2022)
B = 541 (The total number of “citable items” published by that journal in 2021 and 2022)
Then the Impact factor of the Journal should be (1298/541)= 2.40 IF.