I have never seen a medium so I'm not sure. Gracie has a 8" neck, 13" chest. The small fits her nicely. Because there is velcro you can work with the sizing because they are adjustable to the width of your dog. Gracie uses a small but I think a dog some what bigger could wear it also. You just have make sure that you adjust it snugly with the velcro before you snap the clip on top that secures the harness.
Gracie was still a puppy when I got this harness for her. It was really difficult to understand the sizing as every website I saw had different measurements. Also the measurements are different for each style. I ordered an Xsmall at first and it was too small. It was more for a tiny puppy. She has put on a pound since I got it and it still fits well. She is 5 pounds now. I wish I could tell you for sure that a small would fit. She does have room to spare but I'm not sure. Maybe another inch or so room she has left. I guess you just need to make sure that who ever you order from has a good return policy. I ordered Gracie's through Amazon and had no problem returning the first one.
I'm sorry I can't be of more help. Mojo seems to be right between the small and the medium. As I said they are adjustable so it's not like the measurement has to be exact. Most people love it once they get the right size. Let us know how you make out. |