How much does a piece of lumber weigh?

Work out its volume — thickness times width times length — and multiply by the density of the wood. A green softwood at about 35 lb per cubic foot, cut 2 by 6 by 12 feet, is roughly 1 cubic foot of wood and so about 35 pounds. This tool does that for the size and density you enter.

What density should I use for wood?

It depends heavily on the species and how wet the wood is, so density is an editable field here rather than a fixed number. Green, freshly cut lumber is much heavier than kiln-dried; dense hardwoods weigh far more than light softwoods. Look up the figure for your actual material and type it in.

Why does moisture matter so much?

Fresh lumber can hold more than its own dry weight in water, so the same board can weigh nearly twice as much green as it does after it dries. A treated deck board straight off the pile is heavy for this reason. If you are estimating a load to carry or lift, use the wet figure to be safe.

Is this the same as a structural weight?

No. This is the physical weight of the material, useful for handling, shipping and lifting. It says nothing about how much load a member can carry — that is a structural design question, not a weight one, and it is not something this tool addresses.

Lumber weight calculator

This multiplies your sizes into a volume and applies the density you enter, so the answer is only as good as that density — and green wood can weigh nearly double its dry weight. It is a handling and lifting estimate, not a structural figure, and it does not account for hardware, coatings or packaging.

Enter the size of a piece, how many you have, and the density of the wood, and the tool works out the total weight along with the volume it came from. Density is left to you because it is the number that swings the answer most.

Exemple détaillé

A 2 × 6 × 12 ft board is (2 ÷ 12) × (6 ÷ 12) × 12 = 1 cubic foot of wood. At a green softwood density of 35 lb/ft³ that is about 35 lb a board. Ten of them come to 350 lb — worth knowing before you load the truck or carry a bundle up a ladder.

In metric, at the actual size: a 38 × 140 mm board 3.6 m long is 0.038 × 0.14 × 3.6 = 0.0192 m³, and at 560 kg/m³ that is 10.7 kg a board — ten of them 107 kg.

Sur le chantier

Loading the pickup. Forty 2 × 6 × 12s. At the actual size, 1½ × 5½ in, each is 1.5 × 5.5 ÷ 144 × 12 = 0.69 ft³, and at 35 lb/ft³ that is 24 lb — 963 lb for the lift. Run it at the nominal 2 × 6 and the tool says 35 lb a stick and 1,400 lb: a third too heavy, and the difference between one trip and two. (In metric: forty 38 × 140 mm × 3.6 m boards at 560 kg/m³ is about 429 kg.) The truck's payload is on the door sticker; the wood's weight is here.

Lifting a built-up beam. Three 2 × 12 × 20s spiked together: each is 1.5 × 11.25 ÷ 144 × 20 = 2.34 ft³ × 35 = 82 lb, so the beam is 246 lb dry. Green, at 45 lb/ft³, it is 316. Two people on a dry one; the green one wants the lift or a third pair of hands. Type the density for what is actually on the pile.

Sheet goods in the same tool. A ¾ in sheet of plywood is a board 0.75 in thick, 48 in wide, 8 ft long: 0.75 × 48 ÷ 144 × 8 = 2 ft³, and at about 35 lb/ft³ that is roughly 70 lb. A lift of 40 sheets is 2,800 lb — that goes on the forks, not the tailgate.

What went wrong?

Quick referencefor a load

Actual sizes: 2×4 = 1½ × 3½ · 2×6 = 1½ × 5½ · 2×8 = 1½ × 7¼ · 2×10 = 1½ × 9¼ · 2×12 = 1½ × 11¼ · 4×4 = 3½ × 3½
Pounds per foot at 35 lb/ft³: 2×4 1,3 · 2×6 2,0 · 2×8 2,6 · 2×10 3,4 · 2×12 4,1 · 4×4 3,0
A ¾ in 4 × 8 sheet: 2 ft³ — about 70 lb at 35 lb/ft³, a hair less for OSB, more for MDF
Green vs dry: the density field — ask the yard; green can be a third heavier
Kilograms per metre at 560 kg/m³: 38×89 1,9 · 38×140 3,0 · 38×235 5,0 · 38×286 6,1 · 89×89 4,4
Métrique: 35 lb/ft³ = 560 kg/m³ · lb × 0,4536 = kg

Mistakes to catchbefore you trust the number

Typing nominal sizes (2 × 10) when the tool wants actual (1½ × 9¼) — the nominal figure over-weighs a board by about a third.
Using a kiln-dried density for a green treated lift; treated lumber can be half again as heavy fresh from the yard.
Forgetting the count on a lift of 100 pieces and reading the weight of one as the load on the trailer.

La formule

weight = thickness × width × length × density · kg = (mm × mm ÷ 1,000,000) × m × kg/m³

Thickness and width are inches, so dividing each by 12 puts them into feet before multiplying by the length in feet — that gives cubic feet, which times the density in pounds per cubic foot gives pounds. In metric the sizes go to metres and the density is kilograms per cubic metre.

Questions

How much does a piece of lumber weigh?: Work out its volume — thickness times width times length — and multiply by the density of the wood. A green softwood at about 35 lb per cubic foot, cut 2 by 6 by 12 feet, is roughly 1 cubic foot of wood and so about 35 pounds. This tool does that for the size and density you enter.
What density should I use for wood?: It depends heavily on the species and how wet the wood is, so density is an editable field here rather than a fixed number. Green, freshly cut lumber is much heavier than kiln-dried; dense hardwoods weigh far more than light softwoods. Look up the figure for your actual material and type it in.
Why does moisture matter so much?: Fresh lumber can hold more than its own dry weight in water, so the same board can weigh nearly twice as much green as it does after it dries. A treated deck board straight off the pile is heavy for this reason. If you are estimating a load to carry or lift, use the wet figure to be safe.
Is this the same as a structural weight?: No. This is the physical weight of the material, useful for handling, shipping and lifting. It says nothing about how much load a member can carry — that is a structural design question, not a weight one, and it is not something this tool addresses.

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