Lumber weight calculator
Estimate the weight of rectangular boards or a known solid wood volume. Enter actual measured dimensions, not nominal lumber sizes. Species presets represent wood at 12% moisture content; use a matching custom density for green, treated or differently conditioned wood.
Weight formula and units
Weight (kg) = actual solid volume (m³) × density (kg/m³). For identical rectangular boards, volume = actual thickness × actual width × actual length × quantity, with all lengths converted to meters. Pounds = kilograms ÷ 0.45359237.
One inch is 0.0254 m; one foot is 0.3048 m; one cubic foot is 0.028316846592 m³. One actual-volume board foot is 1/12 ft³, or 0.002359737216 m³. A density of 1 lb/ft³ equals approximately 16.018463374 kg/m³.
Species presets and moisture basis
The USDA Forest Products Laboratory 2021 Wood Handbook gives specific gravity based on oven-dry mass and volume at the stated moisture condition. Using Chapter 4, equation 4–14 and Table 4–5, density at 12% moisture is 1,000 × G₁₂ × 1.12 kg/m³. The G₁₂ values below come from Chapter 5, Table 5–3a (pages 5–5, 5–7 and 5–8). They are averages, not guaranteed board weights.
| Species | G₁₂ | Density (kg/m³) |
|---|---|---|
| Douglas-fir (Coast) | 0.48 | 537.6 |
| Western redcedar | 0.32 | 358.4 |
| Ponderosa pine | 0.40 | 448.0 |
| Northern red oak | 0.63 | 705.6 |
| Sugar maple | 0.63 | 705.6 |
Here moisture content is water mass divided by oven-dry wood mass. The 12% presets do not describe green wood or every kiln-dried board. Moisture changes both mass and dimensions; choose custom density when the preset condition does not match.
Checked examples
- Ten actual 1.5 × 3.5 in boards, each 8 ft long, total 2.916667 ft³. Coast Douglas-fir at 12% moisture gives approximately 44.401 kg (97.887 lb) total, or 4.440 kg per board.
- Ten actual 38 × 89 mm boards, each 2.4 m long, have 0.081168 m³ of solid wood. Ponderosa pine at 12% moisture gives 36.363 kg (80.167 lb).
- A measured solid volume of 1 m³ with a custom density of 500 kg/m³ weighs 500 kg (1,102.311 lb).
- 12 actual-volume board feet equal 1 ft³. With a custom density of 35 lb/ft³, the wood weighs 35 lb (15.876 kg).
Limits of a lumber weight estimate
This tool assumes rectangular, solid, identical boards in dimension mode. It does not subtract holes, taper, bark or cutouts. Knots, species variation, treatments and moisture can change density. For plywood, engineered products or mixed bundles, use a verified product density and measured solid volume. Packaging and pallets are excluded. Weigh the shipment when an exact weight is required; this result does not establish lifting capacity, vehicle payload or structural strength.
Accepted limits: thickness/width up to 10 m, length up to 1,000 m, 1–1,000,000 whole boards, total volume up to 1,000,000 m³, and custom density greater than zero and up to 2,000 kg/m³. These input bounds are calculation limits, not suggested lumber sizes.
Related calculators
Use the Board Foot Calculator for lumber volume and cost, the Linear Feet Calculator for required length and stock pieces, or the Density Calculator to derive density from measured mass and volume.