he is about 15.7 inches long. He is a rat terrier so its kinda hard to find things that actually fits him correctly its usually to big on him lol. I got a swim shirt for him and it needs taken up but it keeps him dryer when we swim so he loves it
my sister and I make custom fit dog fleece dog coats that aren't expensive. just e-mail the measurements and we will let you know when its done. they range from 5. to 10. yours would run in the 6. to 7.00
I dnt know how big a sheltie is. the shirt was for a doxie that was 6m old he out grew it fast. the shiet is a medium 13 inches from base of neck to base of tail. thks for looking