Almighty Calculator

Lumber Weight Calculator by Species

Lumber weight is its volume times density; kiln-dried white oak at 12% moisture weighs about 46 lb per cubic foot, or roughly 3.9 lb per board foot.

%
Dry basis, as a moisture meter reads. This model is for 0 to 30%; for greener wood use the log weight calculator.
in
Actual, not nominal.
in
ft
Total weight
212lb
Weight of one piece21.2 lb
Density at this moisture46.4 lb/ft³
Total board feet55 bd ft
Weight per board foot3.86 lb/bd ft

This is a model estimate from average species data. Individual boards vary, so weigh a sample if the weight matters.

Show the math

Basic specific gravity (green volume) = 0.6 (White oak)
At 12% moisture: G = 0.6 ÷ (1 − 0.265 × 0.6 × 0.6) = 0.663
Density = 0.663 × (1 + 12/100) × 62.4 = 46.4 lb/ft³
One piece = 1.5 × 5.5 in × 8 ft ÷ 144 × 46.4 = 21.2 lb
Total = 21.2 × 10 = 212 lb

Rounded the same way as the result above.

How it works

Wood weighs what its cell walls weigh plus the water they hold. The Wood Handbook gives a species’ basic specific gravity (oven-dry weight over green volume) and an equation that adjusts it to any moisture content below the fiber saturation point, where wood has shrunk as it dried.

Multiply that specific gravity by (1 + moisture content) and by the weight of a cubic foot of water, 62.4 lb, to get the density at that moisture. Volume times density is the weight of a piece.

G = G_b ÷ (1 − 0.265 × a × G_b), a = (30 − MC) ÷ 30 Density = G × (1 + MC ÷ 100) × 62.4 lb/ft³ Weight = volume (ft³) × density

Worked example

Ten 1-1/2 × 5-1/2 in white oak boards, 8 ft long, at 12% moisture:

  1. Basic specific gravity (green volume) = 0.6 (White oak)
  2. At 12% moisture: G = 0.6 ÷ (1 − 0.265 × 0.6 × 0.6) = 0.663
  3. Density = 0.663 × (1 + 12/100) × 62.4 = 46.4 lb/ft³
  4. One piece = 1.5 × 5.5 in × 8 ft ÷ 144 × 46.4 = 21.2 lb
  5. Total = 21.2 × 10 = 212 lb
InputValue
SpeciesWhite oak
Moisture content12 %
Thickness1.5 in
Width5.5 in
Length8 ft
Number of pieces10
ResultValue
Total weight212 lb
Weight of one piece21.2 lb
Density at this moisture46.4 lb/ft³
Total board feet55 bd ft
Weight per board foot3.86 lb/bd ft

Assumptions and limits

  • Species data is the USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material (FPL-GTR-282, 2021) basic specific gravity. Individual trees vary widely.
  • The density equation is from the Wood Handbook; it typically lands within about 3% of the tabulated 12% values but can be off by up to about 9% for a few low-density species like basswood.
  • Uses actual dimensions and clear wood; it ignores knots, resin, and treatment chemicals. Below 30% moisture only.

Common questions

How much does a board foot of lumber weigh?

It depends on species and moisture. Kiln-dried white oak is roughly 3.9 lb per board foot; aspen is under half that.

Why does moisture change the weight so much?

Water adds weight in proportion to the dry wood weight: at 12% moisture wood weighs 12% more than oven-dry, and green wood can weigh double.

What about green lumber?

Above about 30% moisture, wood is at full size and the model changes; use the log weight calculator for green wood.

How accurate is it?

It is an estimate from species averages. For shipping or lifting, weigh a sample piece.

Sources

  • USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282): basic specific gravity (Table 5-3a) and Eq. for specific gravity at moisture content G_m = G_b ÷ (1 − 0.265 a G_b), a = (30 − M) ÷ 30.
  • Water weighs 62.4 lb per cubic foot.

Updated 2026-09-30