I wear a 36-37 in Dansko and anywhere from a 6-61/2 M-W. With that, I purchased the 36 Narrow since originally bought the 37 Medium. 37 Medium was huge in length and width. The 36 fits great in length and the Narrow, with the adjustable buckles, fits well. So getting the correct fit is crucial! I don't wear them with socks so I could wear thin socks and adjust the buckles, but I would need the Medium if I wanted to wear regular socks- know that some people live in these shoes no matter the season.