Size 40.5 Medium (US 9.5-10) The Margaux website noted that this shoe runs a bit short, so I think these are more like a 40 / US 9-9.5 Still in box, never worn! Bought but are too narrow for my very wide postpartum feet :( I ended up getting another pair in the wider width and am obsessed, they are so comfortable and classic! From Margaux: With a plush knot detail and effortless feel, this feminine riff on our bestselling block heel will carry you throughout your day in comfort and style. Plush, foam-padded straps for added comfort Italian nappa upper and leather lining 5 mm of foam padding for comfort Walkable 2.5-inch block heel Handmade in Spain