Wood density is mass divided by volume. It helps estimate how much a board or finished project will weigh, but it does not by itself prove strength, stiffness, hardness, decay resistance, or structural capacity. Compare values measured at the same moisture condition, then use the species grade and engineering data required for the actual application.
The quick metric formula is weight (kg) = volume (m³) × density (kg/m³). In US customary units, weight (lb) = volume (ft³) × density (lb/ft³). Actual boards vary within a species, and water adds mass, so a calculated answer is an estimate until the stock is measured and weighed.
Wood density reference table
The approximate averages below are for wood at about 12% moisture content and are derived from the species tables in the USDA Forest Products Laboratory's Wood Handbook: Wood as an Engineering Material. The metric values are rounded conversions from pounds per cubic foot. Growth conditions, proportion of earlywood and latewood, and individual boards create a range around any average.
| Species | kg/m³ | lb/ft³ | Planning note |
|---|---|---|---|
| Eastern white pine | 400 | 25 | Light to carry and easy to machine; dents more readily than denser choices |
| American basswood | 415 | 26 | Light and workable; common for carving rather than wear surfaces |
| Yellow-poplar | 465 | 29 | Moderate weight, workable, and commonly painted |
| Douglas-fir, coast | 545 | 34 | Useful strength-to-weight properties; grade and grain still govern structural use |
| Black cherry | 575 | 36 | Moderate furniture weight with a fine working surface |
| Black walnut | 610 | 38 | Heavier than pine or poplar but below the listed oak and hard maple values |
| White ash | 675 | 42 | Dense and resilient; increases project and component weight |
| Yellow birch | 690 | 43 | Dense, wear resistant, and less forgiving to dull tooling |
| Sugar maple (hard maple) | 705 | 44 | Dense surface for furniture and work tops; preplan lifting and hardware |
| Northern red oak | 705 | 44 | Substantial furniture weight; open pores influence finishing |
| American beech | 720 | 45 | Dense and hard-wearing; moisture control remains important |
| White oak | 755 | 47 | The heaviest species in this comparison; valued where its other properties also fit |
Source: USDA Forest Service, Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-282, especially the physical-property and species tables. Accessed September 1, 2026. Values are reference averages, not a promise about a particular board.
Moisture content changes the answer
Moisture content is the mass of water compared with the oven-dry mass of wood. Green lumber can weigh much more than seasoned stock. Indoors, wood tends toward an equilibrium moisture content that follows surrounding temperature and relative humidity; it continues to gain and lose moisture in service.
A density number is meaningful only with its moisture basis. Some references report oven-dry density, some specific gravity based on green volume, and others weight at 12% moisture content. Do not combine those values as though they were identical. The calculator below uses the 12% table values as planning estimates. If your board is wet, unusually dry, treated, or engineered, use a measured density instead: weigh a rectangular sample, calculate its volume, and divide mass by volume.
Moisture also drives dimensional movement. A heavier wet board does not necessarily become a stronger or more suitable part. Acclimate stock for the intended environment, measure it when the project requires close control, and design joinery to allow cross-grain movement.
How to calculate wood weight
- Measure actual length, width, and thickness. Nominal lumber dimensions are not calculation dimensions.
- Convert all measurements to one volume unit. For inches, cubic feet = length × width × thickness ÷ 1,728.
- Choose a density measured on a comparable moisture basis.
- Multiply volume by density, then multiply by quantity.
- Add separate hardware, finish, glass, fasteners, and other materials to estimate total project weight.
Example: A 36 × 11.25 × 0.75-inch shelf has 303.75 cubic inches, or about 0.176 cubic feet. At 44 lb/ft³, one shelf is approximately 7.73 lb before finish or hardware. Three shelves would be about 23.2 lb. An actual panel may differ because plywood density and moisture vary.
Wood weight calculator
Enter finished dimensions in inches. Select a reference species or enter a custom density in kg/m³. The result updates without sending data anywhere.
Estimated wood weight: 7.74 lb (3.51 kg).
Project-use guide
| Project | Density consideration | Other deciding properties | Useful next check |
|---|---|---|---|
| Wall shelf | Board and contents add load to brackets and wall anchors | Stiffness, span, grade, fastener withdrawal, wall construction | Use a shelf-span calculation and rated mounting hardware |
| Mobile furniture | Dense species increase lifting and caster loads | Joinery, center of gravity, caster rating, floor surface | Estimate complete weight, not wood alone |
| Tabletop | Heft may feel stable but increases base and handling demands | Movement, flatness, stiffness, finish, joinery | Allow seasonal movement across the grain |
| Carving | Lower density often cuts more easily | Grain, hardness, extractives, detail retention | Test tools and finish on an offcut |
| Outdoor project | Density alone does not establish durability | Natural decay resistance, treatment, drainage, exposure rating | Use species and treatment guidance for the actual exposure |
| Structural member | Average density is not a design value | Species, grade, defects, span, load case, code | Use applicable span tables, design values, and professional guidance |
Density is not the same as strength or hardness
Density often correlates with several mechanical properties within comparable material, but it is not a substitute for them. Strength depends on load direction, species, grade, slope of grain, knots, moisture, duration, and defects. Stiffness describes deformation under load. Hardness describes resistance to indentation. Toughness, fastener holding, decay resistance, and dimensional stability are separate decisions.
Engineered panels also need product-specific data. Adhesives, veneers, strands, fibers, and voids change density and performance. Use the manufacturer's current technical sheet when plywood, MDF, OSB, laminated veneer lumber, or another engineered product is the real material.
Measure an actual board when weight matters
For a rectangular sample, measure dimensions accurately, weigh it on a suitable scale, calculate volume, then divide mass by volume. Record moisture content and units. A larger, representative sample usually gives a more useful estimate than a tiny offcut. For a finished project, weighing the assembled object is more reliable than summing reference values.
Use the shoe-rack cut list and material estimate to see dimensions applied to a project, review plywood grades and types before substituting sheet goods, or read the CNC routing guide when density affects machining and workholding.
Sources and further reading
- USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material, FPL-GTR-282. Physical properties, moisture relations, and species tables.
- USDA Forest Service, Wood Handbook publication record. Report metadata, citation, and current download.