6x8 actual size

Nominal, dry and green

A 6x8 is timbers (5 in nominal thickness and up) under the American Softwood Lumber Standard, NIST PS 20-25. The standard names lumber by its nominal size and sets the smallest it may be once it has been dressed (planed smooth). Lumber dried to 19% moisture content or less is held to the dry size; lumber surfaced green, above 19%, is left a little bigger because it shrinks as it dries. The standard notes that timbers are often made and sold without drying, so expect the green size.

Board feet in a 6x8

Thickness × width ÷ 12 gives the board feet in each foot of length. By the nominal size that is 4 bd ft per foot; by the dry dressed size it is 3.323. Ask your yard which one it prices on.

For a whole order, use the board foot calculator. Every size side by side is on the lumber sizes chart.

What a 6x8 weighs per foot

One foot of a dry 6x8, 5-1/2 × 7-1/4 in, at 12% moisture content: its volume × the Wood Handbook’s density, 62.43 lb/ft³ × the species’ specific gravity at 12% × 1.12. Multiply by the length for a whole board. Wetter wood weighs more; the wood weight calculator takes any moisture content.