Got my boots today! Sized up a half size and they fit beautifully. But, I did want the extra room for insoles/socks. I'd say they run 1/2 size small, as I'm usually a solid 39. I ordered a 40 online as well and those will be here tomorrow. I'll return the 39.5 for the 40, I'm guessing, because I do want to wear socks with them. I only walked in them for a few minutes to size them, but they weren't wildly uncomfortable. Many times I have problems with such high heels but I think the support of the boot shaft helped me immensely.