Men's shoe sizes are a standardized system used to determine the fit of footwear for adult males. Sizes typically range from about US size 6 to US size 16, with half sizes available for a more precise fit. The sizing can vary between different countries, with US, UK, and EU sizes being the most common systems. To find the right size, it's important to measure both feet, as they can differ slightly in size. Shoe sizes are based on the length and width of the foot, and many brands offer size charts to help customers choose the best fit for their specific needs.