I wear an 8M, purchased a  9M and was still disappointed. I have never had any luck for myself buying shoes  online. This is the second pair of NB I bought recently and both pair of  different styles have been way too small. We don't have the luxury of a store close to us so I decided to give buying online a try. The color of this style is  nice, but they run narrow and short. I would recommend going to the store and trying them on. The don't have the cushion of most running shoes that I'm used to. I also don't like the way they are priced. Different colors should not be so drastically different in price. If it's the same shoe why the different pricing? I like the free return but I don't have a UPS store with extended hours so I found myself running around after I have worked all night trying to find somewhere to drop them off to return them. If you choose to have them picked up at your home there is a fee of 6 dollars. I bought my husband a pair of 10.5 M which is what he wears and then had to order an 11M and they were fine therfore I bought mine 1 whole size larger and as you can see above they were too small. Disappointed in the women's sizing.