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The wood the piece is cut from; the figure beside each is its basic specific gravity.
The figures are the Wood Handbook's for US-grown wood, oven-dry mass over green volume, and each species also carries its own shrinkage from the Handbook. Construction lumber is often sold as a species group rather than one species; pick the heaviest species the group may contain where the weight matters, or enter a figure of your own with the last choice.
Water in the wood as a percentage of its oven-dry weight; 19% is the most dry softwood lumber may hold.
Read it with a moisture meter, or from the grade stamp: lumber stamped dry holds 19% or less under the American Softwood Lumber Standard, and the Wood Handbook gives kiln-dried softwood dimension lumber an average of 19% or less. Furniture and millwork stock is usually 6% to 8%. Green wood holds far more: the Handbook's Table 4-1 averages 37% for the heartwood of Coast Douglas-fir and 115% for its sapwood, more water than wood. The field goes to 250%.
A sawn piece is a rectangle; a pole or a log is worked as a cylinder.
A log tapers, so enter its diameter at the middle of its length, under the bark, and the cylinder is close to its volume.
What the piece measures, not its nominal size: a dry 2 x 4 is 1-1/2 in (38 mm) thick.
The Wood Handbook's Table 6-6 gives the American Standard dry dressed sizes: 38 mm (1-1/2 in) for nominal 2 in dimension lumber and 89 mm (3-1/2 in) for nominal 4 in. The lumber size page gives the rest. Metric timber is sold by its actual size.
Tools needed: Tape measure
The face width the piece measures: a dry 2 x 4 is 3-1/2 in (89 mm) wide.
Measure across the face. A nominal 2 x 6 dressed dry is 5-1/2 in (140 mm) wide, from the same table.
Tools needed: Tape measure
End to end, along the grain.
Most North American construction lumber comes in lengths that step by 2 ft (610 mm), the Wood Handbook notes; enter the length in hand.
Tools needed: Tape measure
How many of these pieces; the answer is their total weight.
A bundle of one size counts here; a load of mixed sizes is run once for each size and added.
Weight of the lumber
10.2 lb
Worked by the Wood Handbook's Method 1: the species' basic specific gravity, oven-dry mass over green volume, is adjusted for the species' shrinkage from green down to the moisture content entered (none at or above 30%), and the density is water's 1,000 kg/m³ (62.43 pcf) times that specific gravity times one plus the moisture content. The species figures are averages, and a single piece can be 10% or more either side of them.
- Weight of one piece
- 10.21 lb
- Of the total, water
- 1.63 lb
- Density of the wood at this moisture content
- 35.02 pcf
- Specific gravity on the volume at this moisture content
- 0.47
They open the calculator with your figures already in it
Lumber Weight Calculator — Timber Weight by Species and Moisture: 10.21 lb — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material (FPL-GTR-282, 2021), Chapter 4: specific gravity referenced to the volume at a moisture content, always on oven-dry mass; Sx = S0 (1 - x/MCfs), with MCfs taken as 30% where not known (4-9); Gx = Gb / (1 - Sx/100) (4-11); S0 = 26.5 Gb where S0 is not known (4-12, 4-13); density = water density x Gx x (1 + x/100) (4-14), water 1,000 kg/m³ (62.43 lb/ft³); Table 4-3, shrinkage of domestic woods, green to oven-dry; Table 4-6a and 4-6b, density as a function of specific gravity and moisture content; worked example, Gb 0.55, G12 = 0.605, 678 kg/m³ (42.2 lb/ft³) at 12%; a coefficient of variation of about 10% for oven-dry density within common domestic species; Table 4-1, average moisture content of green wood
- USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021), Chapter 5, Table 5-3a, Strength properties of some commercially important woods grown in the United States: specific gravity based on weight when oven-dry and volume when green or at 12% moisture content; the green figure is each species' basic specific gravity here
- USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021), Chapter 6: Table 6-6, American Standard Lumber sizes, nominal 2 x 4 dimension lumber dressed dry to 38 by 89 mm (1-1/2 by 3-1/2 in); softwood lumber less than 114 mm (nominal 5 in) thick dried to 19% moisture content or less is defined as dry by the American Softwood Lumber Standard; construction lumber commonly in 610 mm (2 ft) length multiples
Inputs used
- Species
- Douglas-fir, Coast (0.45)
- Basic Specific Gravity
- 0.45
- Moisture Content (%)
- 19
- Shape of the Piece
- Rectangular: a board, stud, joist or beam
- Actual Thickness
- 1.5 in
- Actual Width
- 3.5 in
- Diameter
- 4 in
- Length of Each Piece
- 8 ft
- Number of Pieces
- 1
Intermediate steps
- Weight of one piece
- 10.21 lb
- Of the total, water
- 1.63 lb
- Density of the wood at this moisture content
- 35.02 pcf
- Specific gravity on the volume at this moisture content
- 0.47
Confidence note: Worked by the Wood Handbook's Method 1: the species' basic specific gravity, oven-dry mass over green volume, is adjusted for the species' shrinkage from green down to the moisture content entered (none at or above 30%), and the density is water's 1,000 kg/m³ (62.43 pcf) times that specific gravity times one plus the moisture content. The species figures are averages, and a single piece can be 10% or more either side of them.
What this calculation does not cover
- The species figures are averages for clear wood. The Wood Handbook puts the variation of oven-dry density within a common species at a coefficient of variation of about 10%, and knots, resin, heartwood and growth rate move a single piece further, so weigh one piece where a load is close to a limit.
- The moisture content is the reader's, and it moves the weight most. Softwood lumber less than 4-1/2 in (114 mm) thick, nominal 5 in, is dry at 19% or less under the American Softwood Lumber Standard, as the Handbook gives it; green timber straight from the saw holds far more, and above about 30% the extra water adds weight without any change in size. A moisture meter gives the figure for the pieces in hand.
- Shrinkage is the species' average from the Handbook's Table 4-3, taken to begin at 30% and to run in a straight line to oven-dry; for a species entered by hand it is the Handbook's estimate, 26.5% times the basic specific gravity. A piece that shrinks more or less than that is a few per cent heavier or lighter per volume than shown below 30%.
- The listed species are US-grown wood from the Handbook's Table 5-3a. The same species grown elsewhere, and the European redwood and whitewood sold in the UK, can differ; enter a basic specific gravity for them from the supplier or a wood reference.
- Solid wood only. Preservative-treated timber carries the treatment and the water it went in with; glulam, LVL, plywood, OSB and other engineered products have densities of their own that their makers publish. Bark on a log or pole is not included.
- Enter the size the piece measures. A nominal size is larger than the piece: a North American 2 x 4 dressed dry is 1-1/2 by 3-1/2 in (38 by 89 mm).
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-10-05 · v1.0.0
Regulatory standards & verification citations3
- USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material (FPL-GTR-282, 2021), Chapter 4: specific gravity referenced to the volume at a moisture content, always on oven-dry mass; Sx = S0 (1 - x/MCfs), with MCfs taken as 30% where not known (4-9); Gx = Gb / (1 - Sx/100) (4-11); S0 = 26.5 Gb where S0 is not known (4-12, 4-13); density = water density x Gx x (1 + x/100) (4-14), water 1,000 kg/m³ (62.43 lb/ft³); Table 4-3, shrinkage of domestic woods, green to oven-dry; Table 4-6a and 4-6b, density as a function of specific gravity and moisture content; worked example, Gb 0.55, G12 = 0.605, 678 kg/m³ (42.2 lb/ft³) at 12%; a coefficient of variation of about 10% for oven-dry density within common domestic species; Table 4-1, average moisture content of green wood
- USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021), Chapter 5, Table 5-3a, Strength properties of some commercially important woods grown in the United States: specific gravity based on weight when oven-dry and volume when green or at 12% moisture content; the green figure is each species' basic specific gravity here
- USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021), Chapter 6: Table 6-6, American Standard Lumber sizes, nominal 2 x 4 dimension lumber dressed dry to 38 by 89 mm (1-1/2 by 3-1/2 in); softwood lumber less than 114 mm (nominal 5 in) thick dried to 19% moisture content or less is defined as dry by the American Softwood Lumber Standard; construction lumber commonly in 610 mm (2 ft) length multiples
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