I wear 48 in basically all Sportiva mountain boots (Nepal, G2SM, older yellow Trangos) and I'm a 14 in every running shoe or US brands. However, I fit in the TX4 in 47.5 pretty well. A lot will depend on the shape of your toes, but I would try them before you decide they don't fit. For reference, the TX4 47.5 fits better than the Boulder X in 48 for me with more room! I also do OK in the older Trango Silver Bullets in 47.5 since that was the biggest size they ever made.