I went with the size chart to determine what size to buy. The number seemed too high when compared to my Birkenstock sizes, but I did it anyway. It's a tiny bit large but okay with socks; so, I am pleased with it. The soles are a bit slippery, but the reviews said they would "rough up" as I used them -- they are not slippery at a dangerous level. So, overall, I am very pleased with this purchase. It's serving exactly the purpose I wanted.