I wear a 9 1/2 us and ordered a 40 Eu. Fit was right. Thought these would be easy to clean and nice shoes for the yard, trips to the pool or water park... Due to the material, they suction to the arch of my foot and make farting sounds when I walk. Really embarrassing to wear in public! Will use for the short walk to the pool and stick to leather and cork for my next pair.