How long does a akita puppy to be fully grown?

My male Akita will be two in September and he is still growing. He is just now starting to fill out a little on top of his height and length. So, my guess is it can take a little over two years before they hit full size. But, I am also trying to find a slightly more accurate answer to this as well. I keep thinking he's done growing in height and length and then he gets bigger. So, if you find a more accurate answer, please let me know.