I ordered the smallest size (US 0-2) and it fit as I expected it to. I found the size chart to be confusing and not at all helpful in deciding what might fit me. My measurements are: 29" around the ribcage underneath the breasts, 31" at the nipples, and 30" beneath the armpits; I usually wear a US women's shirt size XS or XXS. It's a bit tight for me near the armpit area and a bit looser than I expected at the bottom band. I'm pretty small as it is and don't need very much binding to make my chest completely flat, so this is 100% effective for me.