One of the challenges of ordering online is knowing what size to buy. I'm sure we're all aware that even in street shoes, sizes can vary. With pointe shoes, it's even worse - because the best-known pointe shoemakers are all based in different countries, which use different international sizing conventions.
Even if you can find an international shoe conversion chart, it won't necessarily work for pointe shoes - because in many countries, ballet shoe sizing isn't the same as normal shoe sizing.
For that reason, I'm indebted to Danielle deVor of the Perfect Pointe Information Exchange for her work in creating a sizing chart which compares all the major pointe shoe brands and their equivalent sizes. You'll find the chart here:
Please note, the "street shoe size" in this chart is American street shoe size.