Black Walnut wood movement, board-foot & weight calculator
- Janka
- 1,010lbf
- Density
- 38.4lb/ft³
- T/R ratio
- 1.4
- Spec. gravity
- 0.55
Black Walnut is a North American hardwood. It has a Janka side hardness of 1,010 lbf, a specific gravity of 0.55, and an air-dry density near 38 lb/ft³ (615 kg/m³) (mechanical values at 12% moisture content). It shrinks 7.8% tangentially and 5.5% radially from green to oven-dry (T/R ratio 1.4), so a 12-inch flatsawn board moves about 0.19 in (≈ 3/16 in) across a 6-point moisture swing (about 6%→12% MC).
Compute Black Walnut: movement, weight & board footage
Every number below is worked from Black Walnut's own shrinkage and density figures, not looked up from a table — change the width, moisture swing, or board size in the calculators linked alongside.
Cross-grain movement by board width
| Board width | Flatsawn (tangential) | Quartersawn (radial) |
|---|---|---|
| 2″ | 0.031″ (≈ 1/32 in) | 0.022″ (≈ 1/32 in) |
| 3″ | 0.047″ (≈ 1/32 in) | 0.033″ (≈ 1/32 in) |
| 4″ | 0.062″ (≈ 1/16 in) | 0.044″ (≈ 1/32 in) |
| 6″ | 0.094″ (≈ 3/32 in) | 0.066″ (≈ 1/16 in) |
| 8″ | 0.125″ (≈ 1/8 in) | 0.088″ (≈ 3/32 in) |
| 10″ | 0.156″ (≈ 5/32 in) | 0.11″ (≈ 1/8 in) |
| 12″ | 0.187″ (≈ 3/16 in) | 0.132″ (≈ 1/8 in) |
| 16″ | 0.25″ (≈ 1/4 in) | 0.176″ (≈ 3/16 in) |
Need a different width or moisture swing? Run the movement calculator preloaded with Black Walnut. At a T/R ratio of 1.42, Black Walnut is very stable — it moves almost as much radially as tangentially, so flatsawn boards have little reason to cup and wide panels stay flat with ordinary care.
Board footage & weight, standard sizes
| Nominal size × length | Board feet | Weight |
|---|---|---|
| 1×4 × 8′ | 2.67 bd ft | 8.5 lb |
| 1×6 × 8′ | 4 bd ft | 12.8 lb |
| 1×8 × 8′ | 5.33 bd ft | 17.1 lb |
| 1×10 × 8′ | 6.67 bd ft | 21.3 lb |
| 1×12 × 8′ | 8 bd ft | 25.6 lb |
| 2×4 × 8′ | 5.33 bd ft | 17.1 lb |
| 2×6 × 8′ | 8 bd ft | 25.6 lb |
| 2×8 × 8′ | 10.67 bd ft | 34.1 lb |
Different length or size? Run the board foot calculator or the weight calculator, both preloaded with Black Walnut.
Seasonal movement by city
| City | Driest month (EMC) | Most-humid month (EMC) | EMC swing | 12″ board movement |
|---|---|---|---|---|
| Phoenix, AZ | Jun · 4.4% | Dec · 9% | 4.6 pts | 0.144″ (≈ 5/32 in) |
| Chicago, IL | May · 12.3% | Dec · 15.1% | 2.8 pts | 0.087″ (≈ 3/32 in) |
| Miami, FL | Apr · 12.2% | Sep · 14.4% | 2.2 pts | 0.069″ (≈ 1/16 in) |
| Boston, MA | Apr · 11.5% | Sep · 12.8% | 1.3 pts | 0.041″ (≈ 1/32 in) |
| Denver, CO | Jul · 8% | Dec · 10.5% | 2.5 pts | 0.078″ (≈ 1/16 in) |
| Seattle, WA | Jul · 12% | Dec · 16.9% | 4.9 pts | 0.153″ (≈ 5/32 in) |
Driven by Black Walnut's tangential shrinkage of 7.8%. These are outdoor equilibrium-moisture figures, so they are an upper bound — a climate-controlled interior swings less. How this is calculated.
How Black Walnut compares
Ranked against the 196 species in the Wood Handbook tables this site carries.
- Hardness: at 1,010 lbf, Black Walnut is harder than 52% of the 157 species with a Janka figure.
- Weight: at 38.4 lb/ft³ it is heavier than 54% of the 170 species measured — an 8-foot 1×6 board weighs about 12.8 lb.
- Stability: its T/R ratio of 1.42 is more even than 90% of the 196 species here — as humidity changes, 10% of them hold their shape more evenly.
See Black Walnut plotted against every species we carry: the full Janka hardness chart and the full density chart .
Species with a similar working profile
Closest matches on hardness, weight and stability together — useful when Black Walnut is unavailable or priced out.
- Iroko is a common substitute for Black Walnut : 25% harder, about the same weight, and similarly stable in service.
- Black Ash is a common substitute for Black Walnut : 16% softer, 11% lighter, and similarly stable in service.
- Yellow Birch is a common substitute for Black Walnut : 25% harder, 13% heavier, and similarly stable in service.
- True Mahogany is a common substitute for Black Walnut : 21% softer, 18% lighter, and similarly stable in service.
| Species | Janka | Density | T/R |
|---|---|---|---|
| Iroko | 1,260 lbf | 37.7 | 1.36 |
| Black Ash | 850 lbf | 34.2 | 1.56 |
| Yellow Birch | 1,260 lbf | 43.3 | 1.3 |
| True Mahogany | 800 lbf | 31.4 | 1.37 |
About Black Walnut
Black walnut (Juglans nigra) ranges from Vermont to the Great Plains and southward into Louisiana and Texas. About three-quarters of walnut wood is grown in the Central States. The heartwood of black walnut varies from light to dark brown; the sapwood is nearly white and up to 8 cm (3 in.) wide in open-grown trees. Black walnut is normally straight grained, easily worked with tools, and stable in use. It is heavy, hard, strong, and stiff, and has good resistance to shock. Black walnut is well suited for natural finishes. Because of its good properties and interesting grain pattern, black walnut is much valued for furniture, architectural woodwork, and decorative panels. Other important uses are gunstocks, cabinets, and interior woodwork.
Durability & sustainability
Decay resistance: the Wood Handbook rates Black Walnut heartwood resistant to fungal decay . Ratings are for heartwood only and the table's own note cautions that resistance varies substantially within a species; treat this as a general indicator, not a guarantee, especially for ground contact. Wood Handbook, Chapter 14: Biodeterioration of Wood (Arango, Lebow, Glaeser), USDA Forest Products Laboratory, FPL-GTR-282 (2021), Table 14-1. Public domain.
CITES status: not listed on any CITES Appendix — no international-trade restriction applies to Black Walnut.
Properties
| Specific gravity | 0.55 |
|---|---|
| Janka hardness (side) | 1,010 lbf |
| Density (air-dry, 12% MC) | 38.4 lb/ft³ (615 kg/m³) ovendry-weight basis: 34.3 lb/ft³ |
| Weight per board foot (air-dry) | 3.2 lb |
| Radial shrinkage (green→oven-dry) | 5.5% |
| Tangential shrinkage (green→oven-dry) | 7.8% |
| Volumetric shrinkage (green→oven-dry) | 12.8% |
| T/R ratio (stability indicator) | 1.4 |
Shrinkage is total green-to-oven-dry (Table 4-3); strength values are at 12% MC. Full bases and the derivation formulas are on the methodology page.
Data: USDA Forest Products Laboratory, Wood Handbook FPL-GTR-282 (2021), public domain.