Yesterday we put up a couple of posts regarding the vexing matter of bonsai sizes which you can read in the Articles section.
Just to add to that, here is a pictorial back up featuring trees that have won their classifications at BSA shows:
Bob B’s splendid mame juniper – approx height 3.5 inches
John A’s Kifu juniper – approx height 14 inch
John B’s kifu juniper
Interestingly, although John B’s tree is quite a bit taller than the other one, it is the foliage mass that gives it its classification. Both are considered kifu.
And, last but not least, Ian S’s chuhin juniper which is around 18 inches tall.