I turned my pair of Docs size 6 UK, either 39 because I have a strong foot and they returned me horribly in the skin on top of the foot and pressed my foot to the toes. Yet I am of 38.5 but these boots size small to large and strong feet. I have not taken another size because I think that even with a size up to me they come on top. I just ordered the Solovair certainly more expensive but at least they are cut for comfort and will take years because manufactured in UK.