Grey is one of the most universal colors for pants that matches almost any color of shoe. Some shades of grey and charcoal may not match well with certain shoe colors. The final decision about what to wear should always be dictated by what an individual feels looks best.
The Fine Young Gentleman has published a chart that allows readers to check for clashing shoe and pant color combinations. Charts such as this are not definitive. They are intended to be used as a general guide. For example, if a particular shade of grey pants does not look good when paired together with a shade of grey shoes, then individuals should seek a different color combination.