The standard box size of a Chevy Silverado is 78.86 inches long and 51.02 inches wide at the wheelhouse. The long box size is 97.76 inches long and 51.02 inches wide at the wheelhouse. Both have a cargo box height of 21 inches.
The Chevy Silverado long box holds a cargo load of 76.3 cubic feet, while the standard box holds a load of 61 cubic feet. Fully ribbed, skid resistant bed liners are available for all bed lengths. For hauling larger loads, a bed load extender can be added, giving the Chevy Silverado an additional 36-68 inches. While some bed extenders are fastened directly onto the truck bed, larger extenders are attached via tow hitch and are required to have DOT safety flags and reflector tape.