I wear 7-7.5 in US sizes and 37 in Birks. I ordered the 39-40 size and they fit my feet perfectly length-wise, but the shape around the pinky toe joint feels a little weird. Like, it doesn't widen like other shoes (like birks) do. The shoes are still comfortable, though, and I wear these as house slippers. I needed something opened toed and breathable and not fabric so my cat wouldn't rip it up.

Mine were sized fine. Little big, but that works out so I can wash the feet. They are literally $9 shoes, so check your high expectations. The ‘grey’ color is actually a rather gross puss-beige, but IDC - they’re fantastic for the shower. Water goes right through, dry fast, little foot massage while you’re doing your thing. Solid shower shoe. Wear to get a pedi - if no one’s going to see you. ;)

Non-slip. Also may be good for the beach