Black walnut (Juglans nigra) in numbers: hardness, weight, strength, shrinkage, movement and decay resistance, taken from the tables of the USDA Forest Products Laboratory’s Wood Handbook, followed by what the wood is like to work and what it is used for. The values are averages from small, clear, straight-grained test specimens; real boards with knots, sloping grain or a different moisture content will differ.
| Property | Black walnut |
|---|---|
| Janka side hardness, 12% moisture | 1,010 lbf (4,493 N) |
| Janka side hardness, green | 900 lbf |
| Hardness rank | harder than 88 of the 168 woods with a 12% hardness value in our database |
| Density at 12% moisture | 38.5 lb/ft³ (616 kg/m³) |
| Weight per board foot (12%) | 3.20 lb |
| Specific gravity (ovendry weight, green volume) | 0.51 |
| Specific gravity at 12% moisture | 0.55 |
| Bending strength (modulus of rupture), 12% | 14,600 psi |
| Stiffness (modulus of elasticity), 12% | 1.68 million psi |
| Crushing strength (compression parallel to grain), 12% | 7,580 psi |
| Shrinkage green to ovendry: radial / tangential / volumetric | 5.5% / 7.8% / 12.8% |
| Tangential / radial shrinkage ratio | 1.42 |
| Dimensional change per 1% moisture (radial / tangential) | 0.0019 / 0.00274 |
| Impact bending (drop height to failure), 12% | 34 in. |
| Heartwood decay resistance | resistant |
The species in this group
Lumber is often sold under a group name. These are the species the Wood Handbook reports for this group, with the same properties side by side.
| Species | Janka (lbf) | Density (lb/ft³) | Bending (psi) | Stiffness (Mpsi) | Crushing (psi) | Shrink T/R (%) | Decay resistance |
|---|---|---|---|---|---|---|---|
| Black walnut Juglans nigra | 1,010 | 38.5 | 14,600 | 1.68 | 7,580 | 7.8 / 5.5 | resistant |
| Butternut Juglans cinerea | 490 | 26.6 | 8,100 | 1.18 | 5,110 | 6.4 / 3.4 | slightly or nonresistant |
What it is
Black walnut (Juglans nigra) grows from Vermont to the Great Plains and south into Louisiana and Texas; about three-quarters of walnut wood is grown in the Central States. The heartwood ranges from light to dark brown, and the sapwood is nearly white and up to 3 in. wide in open-grown trees. Steaming is commonly used to darken the sapwood so it blends with the heartwood.
Its close relative butternut (Juglans cinerea) is lighter in color, weight and hardness, and is included in the table for comparison.
Working properties
Walnut is normally straight grained, easy to work with tools and stable in use. It is heavy, hard, strong and stiff with good shock resistance, and it is well suited to natural finishes. Its heartwood is in the resistant class for decay.
Weight and density
At 12% moisture content black walnut weighs about 38.5 lb per cubic foot, so one board foot (144 cubic inches) weighs about 3.20 lb. An 8 ft board of actual size 3/4 × 5-1/2 in. (a 1×6) holds 0.229 cubic feet and weighs about 8.8 lb; an 8 ft piece 1-1/2 × 3-1/2 in. (a 2×4 size) weighs about 11.2 lb. Green wood is much heavier because of the water it holds.
Density here is ovendry weight plus 12% water, divided by volume at 12% moisture content (Wood Handbook Eq. 4-12: density = specific gravity at 12% × 62.43 lb/ft³ × 1.12).
Wood movement
The Wood Handbook gives dimensional change coefficients for each species: the fraction of its width a board gains or loses for every 1% change in moisture content, between about 6% and 14%. For black walnut they are 0.00274 across a flatsawn face (tangential) and 0.0019 across a quartersawn face (radial).
Worked example: a flatsawn board 7-1/4 in. wide (a nominal 1×8) that goes from 6% moisture content in a heated winter house to 12% in a humid summer changes width by 7.25 × 0.00274 × 6 = 0.119 in. (about 1/8 in.). The same board quartersawn moves 0.083 in. (about 3/32 in.). Allow for this in panels, tabletops and floors; the wood movement calculator works it out for any size and moisture range.
How it compares
| Species | Janka (lbf) | Density (lb/ft³) | Bending (psi) | Stiffness (Mpsi) | Tangential shrink (%) | Decay resistance |
|---|---|---|---|---|---|---|
| Black walnut | 1,010 | 38.5 | 14,600 | 1.68 | 7.8 | resistant |
| Black cherry | 950 | 35.0 | 12,300 | 1.49 | 7.1 | moderately resistant |
| White oak | 1,360 | 47.5 | 15,200 | 1.78 | 10.5 | resistant |
| Sugar maple | 1,450 | 44.1 | 15,800 | 1.83 | 9.9 | slightly or nonresistant |
| Genuine mahogany (Honduran / big-leaf) | 800 | 33.0* | 11,500 | 1.5 | 4.1 | resistant |
| African mahogany (khaya) | 830 | 31.0* | 10,700 | 1.4 | 4.5 | moderately resistant |
Uses
Furniture, architectural woodwork and decorative panels; gunstocks; cabinets and interior woodwork; turned and carved work.
Frequently asked questions
How hard is black walnut?
Black walnut averages 1,010 lbf (4,493 N) on the Janka side-hardness test at 12% moisture content: harder than black cherry (950 lbf) and softer than the oaks and hard maple.
Is walnut a stable wood?
Yes. Its tangential shrinkage from green to ovendry is 7.8%, lower than the oaks, hard maple and hickory, and the Handbook describes it as stable in use.
How much does black walnut weigh?
About 38.5 lb per cubic foot at 12% moisture content, or 3.20 lb per board foot.
Sources
- USDA Forest Products Laboratory. Wood Handbook: Wood as an Engineering Material. General Technical Report FPL-GTR-190, 2010. Chapter 2 (species descriptions), Chapter 4 (Tables 4-3, 4-4 shrinkage; Eq. 4-7, 4-9, 4-12 density), Chapter 5 (Tables 5-3b, 5-5b strength and hardness), Chapter 13 (Table 13-5 dimensional change coefficients), Chapter 14 (Table 14-1 decay resistance)
- USDA Forest Products Laboratory. Wood Handbook, 2021 edition (FPL-GTR-282)
Last reviewed: 22 October 2026. Numbers are generated from our parsed copy of the Handbook tables, so every page uses the same data. Values marked * are estimates computed with the Handbook’s own equations. Spotted an error? Please let us know.