2 Kings 24:8 (ESV)

8 Jehoiachin was eighteen years old when he became king, and he reigned three months in Jerusalem. His mother’s name was Nehushta the daughter of Elnathan of Jerusalem.

According to most Hebrew manuscripts of 2 Chronicles 36:9, Jehoiachin was not eighteen, but eight years old (although the ESV has eighteen) when he became king. This is the first difference between Kings and Chronicles. The second difference is that Kings mentions a reign of three months, while Chronicles has three months and ten days. There is the explanation that the ten in Chronicles is to be added to the eight (of his age); and various translations does indeed translate 2 Chronicles 36:9 like this. It should be noted, however, that this is not a literal translation. This solution eliminates the differences between Kings and Chronicles. What is also possible is that a miswriting has taken place in Chronicles and that we should read eighteen instead of eight. The eight years is not to be seen as an author's error, but a copyist’s transcribing error.

In mentioning the duration of the reign, Chronicles is very accurate and where Kings gives the rough number of three months, the writer of Chronicles is exact: three months plus ten days. Chronicles is more succinct here, but that does not mean it is less accurate.