How thick a silver chain for men should be really depends on the type of look that you want to achieve.  A mens’ silver chain necklace that’s 2-3 mm thick is classic yet subtle, allowing you to wear it alone for elevated everyday style, or to layer with additional necklaces for a statement look.  A silver men’s chain measuring 4-5 mm in width is versatile enough to suit a wide range of styles. These types of chains look particularly good in a box or curb link style—still bold enough to stand out without overshadowing the rest of your pieces.   A silver men's chain between 6-10 mm is eye-catching, ideal if you're looking to make a statement.