2 Kings 24:18
Zedekiah was twenty and one years old when he began to reign, and he reigned eleven years in Jerusalem. And his mother's name was Hamutal, the daughter of Jeremiah of Libnah.

2 Chronicles 36:11
Zedekiah was one and twenty years old when he began to reign, and reigned eleven years in Jerusalem.

Jeremiah 28:1
And it came to pass the same year, in the beginning of the reign of Zedekiah king of Judah, in the fourth year, and in the fifth month, that Hananiah the son of Azur the prophet, which was of Gibeon, spake unto me in the house of the LORD, in the presence of the priests and of all the people, saying,