I find it varies; I brought home a medium for Pablo last week and had to return it; too small. Other mediums he swims in. He's burly through the shoulders and chest, so he's hard to fit. Anybody with smaller Chis have any ideas for leiarandy?
The things that I have gotten have either been sized by weight or an inches measurement from base of neck to base of tail.
My girls are 3-ish pounds and wear an XS or an XXS. One likes clothes. One hates them so I usually leave them naked.
I make chi/dog clothes, so the fit can be adjusted to perfectly fit your specific dog and size. You would need to give me his size you normally put him in and specifics like length, etc.