What is the actual width of a standard 2 x 8 piece of surfaced dry S4S framing lumber?

The actual width of a standard 2 x 8 piece of surfaced dry S4S (Surfaced Four Sides) framing lumber is indeed 7 1/4 inches. This measurement stems from the manufacturing process where nominal lumber sizes refer to dimensions before drying and surfacing. The nominal size "2 x 8" indicates the dimensions that are commonly used in the lumber industry, but the actual dimensions are slightly smaller due to drying and planing processes.

When lumber is dried and planed, the dimensions can change. For a 2 x 8, the actual width is reduced to 7 1/4 inches, while the thickness measures at 1 1/2 inches. This discrepancy is standard across various sizes of dimensional lumber and is essential for carpenters and builders to understand when specifying materials for construction projects.