Kaedyn is 15 inches (give or take .5 inches). Kai is 17.5 inches. Kai's a bit of a throw-off as far a typical Sheltie appearances go. He has a huge frame and is way longer than Kaedyn. His face is a bit off too. Kaedyn's a bit off of typical appearances as well but he's actually quite small.. he's pretty much at the expected size for Shelties. I've noticed a lot of agility (and flyball) Shelties are quite small though so maybe that's why my boys seem a bit big lol.