WOOD BEAM SIZINGTM Beam size

WBS shows both the nominal and actual beam size. Beam sizing calculations are always based on the actual size.

Width and depth refer to the beam in place in the structure. Usually, the depth, always the vertical dimension, is larger than the width.

Here's a 2x12 in place for example. The nominal width is 2-inches and the nominal depth is 12-inches.

Structural engineering formulae refer to the depth as d but to the width as
b for breadth.

Common usage however refers to the same 2x12, before being installed, as
2-inches thick and 12-inches wide.

For 2x12 planking, sized flatwise in
WBS Basic, enter 12 as the width and 2 as the depth.

ACTUAL DIMENSIONS

Dimension lumber: WBS Basic shows kiln-dried sizes - subtracting 1/2-inch off the nominal width and either 1/2-inch (d <= 7) or 3/4-inch off the nominal depth.

2x6 equals 1-1/2 inches by 5-1/2 inches
2x12 equals 1-1/2 inches by 11-1/4 inches

Beams: WBS Basic takes 1/2-inch off each nominal dimension.

WBS BEAM SIZE PANEL

2x12 beam is shown with the actual size as 1-1/2 inches by 11-1/4 inches