Albert Barnes Commentary 2 Chronicles 26:13

"And under their hand was an army, three hundred thousand and seven thousand and five hundred, that made war with mighty power, to help the king against the enemy." — 2 Chronicles 26:13 (ASV)

(Compare to 2 Chronicles 25:5). It is clear that Uzziah had not added much to the military strength of the nation by his conquests. His army exceeded that of his father Amaziah by only 7,500 men.