I went to the store to find my size. I had to go down a size in this style. I should be a 39 but there 38s fit perfect. The Birkenstock site says you need them to be a little bigger but its hard because they don't come in half sizes.
I didn't like this style as much as the other birkenstocks with straps because there is only one really narrow band across your toes and just wearing it around the house it was starting to rub, so I am sending these back. I do love the ankle strap part so I ordered the Kaylas and like them better