Twentieth year — The meaning is, that he began his reign in the twentieth year after the beginning of Jotham's reign; or, which is the same thing, in the fourth year of Ahaz, son of Jotham.
Related Commentaries of 2 Kings 15:30
2 Kings 15:30
30 And Hoshea the son of Elah made a conspiracy against Pekah the son of Remaliah, and smote him, and slew him, and reigned in his stead, in the twentieth year of Jotham the son of Uzziah.