Depending on the shoe manufacturer I can usually wear anything from a 4.5 to a 5.5 (or a kids 3....). My Sidi's are 37's, in other brands I need a 36. Sidi definitely goes down to 36 (I found a pair of Dom's on sale for $40 once and no matter what I did I could not squeeze my foot into that darn 36...) but I did find a killer deal on my road shoes- I got my $300 Sidi's for $30, since they'd been in the store for a couple of years...