In 2 Kings 24:12And Jehoiachin the king of Judah went out to the king of Babylon, he, and his mother, and his servants, and his princes, and his officers: and the king of Babylon took him in the eighth year of his reign.
See All..., what does the "8th year" refer to?

2 Kings 24:12And Jehoiachin the king of Judah went out to the king of Babylon, he, and his mother, and his servants, and his princes, and his officers: and the king of Babylon took him in the eighth year of his reign.
See All... - "And Jehoiachin the king of Judah went out to the king of Babylon, he, and his mother, and his servants, and his princes, and his officers: and the king of Babylon took him in the eighth year of his reign."

This is the eighth year of the reign of Nebuchadnezzar. According to 2 Kings 24:8Jehoiachin was eighteen years old when he began to reign, and he reigned in Jerusalem three months. And his mother's name was Nehushta, the daughter of Elnathan of Jerusalem.
See All..., Jehoiachin only reigned three months, so it could not be the eighth year of his reign. Also, according to Jeremiah 25:1The word that came to Jeremiah concerning all the people of Judah in the fourth year of Jehoiakim the son of Josiah king of Judah, that was the first year of Nebuchadrezzar king of Babylon;
See All..., the first year of Nebuchadnezzar's reign was in the fourth year of the reign of Jehoiakim (ending with "m" and not with "n"), who was Jehoiachin's father and who reigned a total of eleven years. This would match perfectly with 2 Kings 24:12And Jehoiachin the king of Judah went out to the king of Babylon, he, and his mother, and his servants, and his princes, and his officers: and the king of Babylon took him in the eighth year of his reign.
See All... being the eighth year of the reign of Nebuchadnezzar.