What is the relationship between the size of a lumber board and its marketed dimension?

The marketed size of lumber is often larger than the actual size due to the way lumber is processed and sold. When lumber is cut, it begins with rough dimensions, and as it is dried and planed to smooth the surfaces, it loses some material. For instance, a board that starts as a "2x4" is typically finished to about "1.5x3.5" after drying and planing. This discrepancy arises because the initial cutting measurements refer to the dimension before any finishing processes take place.

In the lumber industry, this difference is a standard practice and is generally accepted by consumers. Recognizing that the marketed dimensions reflect the nominal size, rather than the true dimensions post-processing, is essential for contractors and carpenters when planning and purchasing materials. Understanding this relationship helps ensure that projects are designed with the correct measurements in mind to avoid any miscalculations in construction.

The choices regarding equality or being smaller than the actual size do not reflect this standard practice, and variations by type of wood may imply different processes but do not alter the fundamental relationship of marketed versus actual sizes. Thus, the correct answer highlights the industry norm where marketed dimensions are larger than what one can expect when measuring finished lumber.