Quick answer
Lumber weight = thickness × width × length × pieces × density of the species. One 1.5 × 3.5 inch loblolly pine board 8 ft long weighs about 10.4 lb (4.72 kg), using a density of 571 kg/m³ at 12% moisture.
Enter the species, dimensions and pieces. The calculator returns total weight, weight per piece and volume.
Related tools: Wood Weight Calculator: Weight of a volume of wood by species (air-dried, 12% moisture). Square Footage Calculator: Area of a rectangular space in square feet, square metres and square yards. Concrete Calculator: Cubic yards of concrete for a slab, plus bag counts.
How to use the Lumber Weight Calculator
- Choose species: Alder, red, Ash, black, Ash, blue, Ash, green, Ash, Oregon and Ash, white and 105 more.
- Enter thickness (0.001 or more).
- Enter width (0.001 or more).
- Choose thickness and width unit: Inches, Millimetres and Centimetres.
- Enter length (0.001 or more).
- Choose length unit: Feet, Metres and Inches.
- Enter pieces (a whole number, between 1 and 100000). It starts at 1.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Species | Choose one: Alder, red; Ash, black; Ash, blue; Ash, green; Ash, Oregon; Ash, white; Aspen, bigtooth; Aspen, quaking; … | Starts at Pine, loblolly |
| Thickness | A number | ≥ 0.001 |
| Width | A number | ≥ 0.001 |
| Thickness and width unit | Choose one: Inches; Millimetres; Centimetres | Starts at Inches |
| Length | A number | ≥ 0.001 |
| Length unit | Choose one: Feet; Metres; Inches | Starts at Feet |
| Pieces | A whole number | ≥ 1, ≤ 100000, starts at 1 |
Formula and method
Formula
weight = thickness × width × length × pieces × (specific gravity at 12% MC × 1.12 × 1,000 kg/m³)
IEEE-754 double precision; shown to at most 6 decimal places.
Weight is for air-dried wood at 12% moisture content: the Wood Handbook's specific gravity is the ovendry weight divided by the volume at 12% moisture, so density = specific gravity × 1.12 × 1,000 kg/m³. Values are species averages for clear wood from the Handbook's test samples; real boards vary by tree, growth rate and moisture, and green or wet lumber is much heavier. Enter the actual (dressed) dimensions, not the nominal ones: a nominal 2×4 is about 1.5 × 3.5 in.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Species = Pine, loblolly; Thickness = 1.5; Width = 3.5; Thickness and width unit = Inches; Length = 8; Length unit = Feet; Pieces = 1.
| Result | Value |
|---|---|
| Total weight | 10.4 lb |
| Kilograms | 4.72 kg |
| Weight per piece | 10.4 lb |
| Volume per piece | 8.259 L |
| Density used | 571 kg/m³ |
Example 2
Inputs: Species = Douglas-fir, coast; Thickness = 1.5; Width = 5.5; Thickness and width unit = Inches; Length = 12; Length unit = Feet; Pieces = 10.
| Result | Value |
|---|---|
| Total weight | 230.73 lb |
| Kilograms | 104.66 kg |
| Weight per piece | 23.07 lb |
| Volume per piece | 19.468 L |
| Density used | 538 kg/m³ |
Example 3
Inputs: Species = Oak, white (white oak group); Thickness = 19; Width = 140; Thickness and width unit = Millimetres; Length = 2.4; Length unit = Metres; Pieces = 4.
| Result | Value |
|---|---|
| Total weight | 42.88 lb |
| Kilograms | 19.45 kg |
| Weight per piece | 10.72 lb |
| Volume per piece | 6.384 L |
| Density used | 762 kg/m³ |
The first line is the headline result (total weight). Below it the lumber Weight Calculator lists kilograms, weight per piece, volume per piece and density used, which describe the same case from other angles. IEEE-754 double precision; shown to at most 6 decimal places.
Species and moisture
Wood weight varies with species and moisture. The calculator uses the average density of clear air-dried wood at 12% moisture. Green lumber can weigh 50% or more extra because of water.
Estimates only
Knots, resin and growth rings change real weights, and treated lumber is heavier because of preservative. Use the result for planning loads and transport, not for structural design.
How the result changes with thickness
Holding every other input at the first worked example, this table changes only thickness. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Thickness | Total weight | Kilograms | Weight per piece |
|---|---|---|---|
| 0.75 | 5.2 lb | 2.36 kg | 5.2 lb |
| 1.5 | 10.4 lb | 4.72 kg | 10.4 lb |
| 3 | 20.8 lb | 9.44 kg | 20.8 lb |
| 6 | 41.6 lb | 18.87 kg | 41.6 lb |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Thickness: left empty shows "Enter thickness." beside that field and no result.
- Length: entering "0" shows "Length must be at least 0.001." beside that field and no result.
- Pieces: entering "0" shows "Pieces must be at least 1." beside that field and no result.
Choosing between the Lumber Weight Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Wood Weight Calculator](/construction/wood-weight-calculator/) | species, volume and volume unit | Weight |
| [Square Footage Calculator](/construction/square-footage-calculator/) | length, width and unit | Area |
| [Concrete Calculator](/construction/concrete-calculator/) | length, width and depth / thickness | Cubic yards |
| [Gravel Calculator](/construction/gravel-calculator/) | length, width and depth / thickness | Cubic yards |
| [Board Foot Calculator](/construction/board-foot/) | thickness, width and length | Board feet |
Background: construction estimates
Material quantities are geometry plus a margin. Calculate the exact volume or area, add an allowance for waste, spillage, cuts and uneven ground (calculator pages commonly mention 5 to 10 percent, a rule of thumb that varies by material and job) and round up to whole units. One cubic yard is exactly 27 cubic feet.
Suppliers often have minimum order sizes and may charge for small loads, so confirm quantities, product yields and local code with your supplier or a qualified estimator before ordering.
Assumptions and limitations
- Air-dried (12% moisture) weight only
- Species averages for clear wood; knots, resin and moisture change real weight
Quantities are estimates. Add allowances for waste and site conditions, and follow local codes and a qualified professional's instructions for structural or safety-critical work.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for thickness, length and pieces to confirm this.
Frequently asked questions
How much does a 2×4 weigh?
An 8 ft pine 2×4 is around 10 lb.
Why is wet lumber heavier?
Wet or green lumber contains water, which adds weight.
Does nominal size matter?
Enter actual dimensions, 1.5 × 3.5 for a 2×4.
What does the Lumber Weight Calculator calculate?
Weight of boards or beams from species, actual dimensions and quantity (air-dried, 12% moisture). It returns Total weight, Kilograms, Weight per piece, Volume per piece and Density used.
What formula does the Lumber Weight Calculator use?
weight = thickness × width × length × pieces × (specific gravity at 12% MC × 1.12 × 1,000 kg/m³). Weight is for air-dried wood at 12% moisture content: the Wood Handbook's specific gravity is the ovendry weight divided by the volume at 12% moisture, so density = specific gravity × 1.12 × 1,000 kg/m³.
What do I need to enter in the lumber Weight Calculator?
You enter Species, Thickness, Width, Thickness and width unit, Length, Length unit and Pieces.
How is the result rounded or limited?
IEEE-754 double precision; shown to at most 6 decimal places. Air-dried (12% moisture) weight only.
What are the limits of this calculator?
Air-dried (12% moisture) weight only. Species averages for clear wood; knots, resin and moisture change real weight.
What does the “Thickness and width unit” option change?
It sets how the lumber Weight is worked out. The choices are Inches, Millimetres and Centimetres.
What is an example of a lumber Weight result?
With species Pine, loblolly, thickness 1.5, width 3.5, thickness and width unit Inches and length 8, the total weight is 10.4 lb.
Where does the method come from?
The method follows: USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material (FPL-GTR-282, 2021), Chapter 5, Table 5-3a: specific gravity at 12% moisture content (public domain), https://research.fs.usda.gov/treesearch/62244; Wood Handbook Chapter 4: density at moisture content m = ovendry weight × (1 + m/100) per volume at that moisture content.
Can I rely on this calculator for a decision?
Quantities are estimates. Add allowances for waste and site conditions, and follow local codes and a qualified professional's instructions for structural or safety-critical work. For this calculator in particular: Air-dried (12% moisture) weight only.
Related calculators
- Wood Weight Calculator — Weight of a volume of wood by species (air-dried, 12% moisture).
- Square Footage Calculator — Area of a rectangular space in square feet, square metres and square yards.
- Concrete Calculator — Cubic yards of concrete for a slab, plus bag counts.
- Gravel Calculator — Cubic yards of gravel for an area.
- Board Foot Calculator — Board feet of lumber from thickness, width and length.
- Mulch Calculator — Cubic yards of mulch for a bed.
Sources
- USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material (FPL-GTR-282, 2021), Chapter 5, Table 5-3a: specific gravity at 12% moisture content (public domain), https://research.fs.usda.gov/treesearch/62244
- Wood Handbook Chapter 4: density at moisture content m = ovendry weight × (1 + m/100) per volume at that moisture content
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.