The North Face M Verto Alpine Gore-Tex Men's Outdoor Shoes

Hello, the M Verto Alpine Gore-Tex model is a standard fit outdoor shoe. In your case, you can check whether both size 40 and size 40.5 are available from the size options on the product page. If your size 40 fits your feet perfectly, it would be best to choose this. However, if you plan on wearing thick winter socks or prefer a slightly roomier fit, you might want to consider size 40.5. The decision is entirely up to you — you can see the available numbers on the product page.