Bubinga wood movement, board-foot & weight calculator
- Janka
- 2,690lbf
- Density
- 49.6lb/ft³
- T/R ratio
- 1.4
- Spec. gravity
- 0.71
Bubinga (Guibourtia spp.) is an imported species. It has a Janka side hardness of 2,690 lbf, a specific gravity of 0.71, and an air-dry density near 50 lb/ft³ (795 kg/m³) (mechanical values at 12% moisture content). It shrinks 8.4% tangentially and 5.8% radially from green to oven-dry (T/R ratio 1.4), so a 12-inch flatsawn board moves about 0.2 in (≈ 3/16 in) across a 6-point moisture swing (about 6%→12% MC).
Compute Bubinga: movement, weight & board footage
Every number below is worked from Bubinga'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″ | 0.034″ (≈ 1/32 in) | 0.023″ (≈ 1/32 in) |
| 3″ | 0.05″ (≈ 1/16 in) | 0.035″ (≈ 1/32 in) |
| 4″ | 0.067″ (≈ 1/16 in) | 0.046″ (≈ 1/32 in) |
| 6″ | 0.101″ (≈ 3/32 in) | 0.07″ (≈ 1/16 in) |
| 8″ | 0.134″ (≈ 1/8 in) | 0.093″ (≈ 3/32 in) |
| 10″ | 0.168″ (≈ 5/32 in) | 0.116″ (≈ 1/8 in) |
| 12″ | 0.202″ (≈ 3/16 in) | 0.139″ (≈ 1/8 in) |
| 16″ | 0.269″ (≈ 9/32 in) | 0.186″ (≈ 3/16 in) |
Need a different width or moisture swing? Run the movement calculator preloaded with Bubinga. At a T/R ratio of 1.45, Bubinga 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 | 11 lb |
| 1×6 × 8′ | 4 bd ft | 16.5 lb |
| 1×8 × 8′ | 5.33 bd ft | 22 lb |
| 1×10 × 8′ | 6.67 bd ft | 27.6 lb |
| 1×12 × 8′ | 8 bd ft | 33.1 lb |
| 2×4 × 8′ | 5.33 bd ft | 22 lb |
| 2×6 × 8′ | 8 bd ft | 33.1 lb |
| 2×8 × 8′ | 10.67 bd ft | 44.1 lb |
Different length or size? Run the board foot calculator or the weight calculator, both preloaded with Bubinga.
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 | 0.155″ (≈ 5/32 in) |
| Chicago, IL | May · 12.3% | Dec · 15.1% | 2.8 pts | 0.094″ (≈ 3/32 in) |
| Miami, FL | Apr · 12.2% | Sep · 14.4% | 2.2 pts | 0.074″ (≈ 1/16 in) |
| Boston, MA | Apr · 11.5% | Sep · 12.8% | 1.3 pts | 0.044″ (≈ 1/32 in) |
| Denver, CO | Jul · 8% | Dec · 10.5% | 2.5 pts | 0.084″ (≈ 3/32 in) |
| Seattle, WA | Jul · 12% | Dec · 16.9% | 4.9 pts | 0.165″ (≈ 5/32 in) |
Driven by Bubinga's tangential shrinkage of 8.4%. These are outdoor equilibrium-moisture figures, so they are an upper bound — a climate-controlled interior swings less. How this is calculated.
How Bubinga compares
Ranked against the 196 species in the Wood Handbook tables this site carries.
- Hardness: at 2,690 lbf, Bubinga is harder than 94% of the 157 species with a Janka figure — firmly in the hard quarter, which is what resists denting in flooring and worktops.
- Weight: at 49.6 lb/ft³ it is heavier than 86% of the 170 species measured — an 8-foot 1×6 board weighs about 16.5 lb.
- Stability: its T/R ratio of 1.45 is more even than 88% of the 196 species here — as humidity changes, 12% of them hold their shape more evenly.
See Bubinga plotted against every species we carry: the full Janka hardness chart and the full density chart .
About Bubinga
Although benge (Guibourtia arnoldiana), ehie or ovangkol (Guibourtia ehie), and bubinga (Guibourtia spp.) belong to the same West African genus, they differ rather markedly in color and somewhat in texture. The bubinga species are listed in CITES Appendix II. The heartwood of benge is pale yellowish brown to medium brown with gray to almost black stripes. Ehie heartwood tends to be more golden brown to dark brown with gray to almost black stripes. Bubinga heartwood is pink, vivid red, or red–brown with purple streaks, and it becomes yellow or medium brown with a reddish tint upon exposure to air. The texture of ehie is moderately coarse, whereas that of benge and bubinga is fine to moderately fine. All three woods are moderately hard and heavy, but they can be worked well with hand and machine tools. They are listed as moderately durable and resistant to preservative treatment. Drying may be difficult, but with care, the wood dries well. These woods are used in turnery, flooring, furniture components, cabinetwork, and decorative veneers.
Durability & sustainability
Decay resistance: the Wood Handbook rates Bubinga heartwood moderately 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: Bubinga is listed on CITES Appendix II, which restricts international trade. The Guibourtia species traded as bubinga are listed on CITES Appendix II (added 2017, in response to a surge in demand and over-harvest).
Properties
| Specific gravity | 0.71 |
|---|---|
| Janka hardness (side) | 2,690 lbf |
| Density (air-dry, 12% MC) | 49.6 lb/ft³ (795 kg/m³) ovendry-weight basis: 44.3 lb/ft³ |
| Weight per board foot (air-dry) | 4.13 lb |
| Radial shrinkage (green→oven-dry) | 5.8% |
| Tangential shrinkage (green→oven-dry) | 8.4% |
| Volumetric shrinkage (green→oven-dry) | 14.2% |
| T/R ratio (stability indicator) | 1.4 |
Shrinkage is total green-to-oven-dry (Table 4-4); 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.