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Woodworking Math

5/4x10 actual size

Dry (19% moisture or less)

1 × 9-1/4 in

25.4 × 235 mm

From the standard, NIST PS 20-25

End view to scale: dashed is the nominal 5/4x10, filled is the dry dressed size.

Nominal, dry and green

SizeThicknessWidth
Nominal (the name)1-1/4 in10 in
Dry, minimum1 in (25.4 mm)9-1/4 in (235 mm)
Green, minimum1-1/32 in (26.2 mm)9-1/2 in (241.3 mm)

A 5/4x10 is boards (under 2 in nominal thickness) 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.

Board feet in a 5/4x10

Thickness × width ÷ 12 gives the board feet in each foot of length. By the nominal size that is 1.042 bd ft per foot; by the dry dressed size it is 0.771. Ask your yard which one it prices on.

LengthNominal bd ftActual (dry) bd ft
8 ft8.336.17
10 ft10.427.71
12 ft12.59.25
16 ft16.6712.33

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

What a 5/4x10 weighs per foot

One foot of a dry 5/4x10, 1 × 9-1/4 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.

SpeciesSpecific gravity (12%)Weight per foot
Douglas-fir (coast)0.482.16 lb
Southern pine (loblolly)0.512.29 lb
Western hemlock0.452.02 lb
Eastern white pine0.351.57 lb
White spruce0.361.62 lb

One source: USDA Forest Products Laboratory, the authority for species properties it measured

Work it out for your project

Sources

  1. NIST (US Department of Commerce), Voluntary Product Standard PS 20-25, American Softwood Lumber Standard, Table 3 (effective January 2025), read 2026-11-07
  2. Engineering ToolBox, Softwood lumber: nominal and actual (dry) sizes, read 2026-11-07
  3. WoodBin, Standard dimensions of lumber (hardwood thickness after G. Wengert; softwood dry and green sizes), read 2026-11-07

How we source these numbers