I usually where a size 9 1/2-10 men's, and of course Crocs don't come in half sizes shoes. I remember buying the clog at a size 10 and they were big so when I bought these I went with a 9 hoping it to be the same.
So when I got them it was a struggle to put them on. The fabric use just wouldn't stretch. The wierd part is when I did manage the lenght was actually perfect for my foot. The problem seem to be the fabric used. It doesn't give what so ever and hurt. The top of my feet and the the heel was in pain no matter if I stood or sat down.  I was at a point where I was about to return them, but decided to look at the soles that came with the shoes. Let me tell you they are great but they are super thick. Honestly I would of been happy with just the button being the same style as the clog.
Anyways I took the soles out wore the shoes again and my god what a difference. My feet slid in with ease and no tightness what so ever. It was like night and day.
So instead of returning them. I decided to buy a thinner sole to replace the one that came with the shoe.