Sweetgum wood movement, board-foot & weight calculator
- Janka
- 850lbf
- Density
- 36.3lb/ft³
- T/R ratio
- 1.9
- Spec. gravity
- 0.52
Sweetgum is a North American hardwood. It has a Janka side hardness of 850 lbf, a specific gravity of 0.52, and an air-dry density near 36 lb/ft³ (581 kg/m³) (mechanical values at 12% moisture content). It shrinks 10.2% tangentially and 5.3% radially from green to oven-dry (T/R ratio 1.9), so a 12-inch flatsawn board moves about 0.24 in (≈ 1/4 in) across a 6-point moisture swing (about 6%→12% MC).
Compute Sweetgum: movement, weight & board footage
Every number below is worked from Sweetgum'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″ | 0.041″ (≈ 1/32 in) | 0.021″ (≈ 1/32 in) |
| 3″ | 0.061″ (≈ 1/16 in) | 0.032″ (≈ 1/32 in) |
| 4″ | 0.082″ (≈ 3/32 in) | 0.042″ (≈ 1/32 in) |
| 6″ | 0.122″ (≈ 1/8 in) | 0.064″ (≈ 1/16 in) |
| 8″ | 0.163″ (≈ 5/32 in) | 0.085″ (≈ 3/32 in) |
| 10″ | 0.204″ (≈ 7/32 in) | 0.106″ (≈ 3/32 in) |
| 12″ | 0.245″ (≈ 1/4 in) | 0.127″ (≈ 1/8 in) |
| 16″ | 0.326″ (≈ 5/16 in) | 0.17″ (≈ 5/32 in) |
Need a different width or moisture swing? Run the movement calculator preloaded with Sweetgum. At a T/R ratio of 1.92, Sweetgum is stable — it moves moderately more across the face than through the thickness — normal behaviour for a furniture hardwood, and predictable if boards are acclimatised before milling.
Board footage & weight, standard sizes
| Nominal size × length | Board feet | Weight |
|---|---|---|
| 1×4 × 8′ | 2.67 bd ft | 8.1 lb |
| 1×6 × 8′ | 4 bd ft | 12.1 lb |
| 1×8 × 8′ | 5.33 bd ft | 16.1 lb |
| 1×10 × 8′ | 6.67 bd ft | 20.2 lb |
| 1×12 × 8′ | 8 bd ft | 24.2 lb |
| 2×4 × 8′ | 5.33 bd ft | 16.1 lb |
| 2×6 × 8′ | 8 bd ft | 24.2 lb |
| 2×8 × 8′ | 10.67 bd ft | 32.3 lb |
Different length or size? Run the board foot calculator or the weight calculator, both preloaded with Sweetgum.
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 | 0.188″ (≈ 3/16 in) |
| Chicago, IL | May · 12.3% | Dec · 15.1% | 2.8 pts | 0.114″ (≈ 1/8 in) |
| Miami, FL | Apr · 12.2% | Sep · 14.4% | 2.2 pts | 0.09″ (≈ 3/32 in) |
| Boston, MA | Apr · 11.5% | Sep · 12.8% | 1.3 pts | 0.053″ (≈ 1/16 in) |
| Denver, CO | Jul · 8% | Dec · 10.5% | 2.5 pts | 0.102″ (≈ 3/32 in) |
| Seattle, WA | Jul · 12% | Dec · 16.9% | 4.9 pts | 0.2″ (≈ 3/16 in) |
Driven by Sweetgum's tangential shrinkage of 10.2%. These are outdoor equilibrium-moisture figures, so they are an upper bound — a climate-controlled interior swings less. How this is calculated.
How Sweetgum compares
Ranked against the 196 species in the Wood Handbook tables this site carries.
- Hardness: at 850 lbf, Sweetgum is harder than 44% of the 157 species with a Janka figure.
- Weight: at 36.3 lb/ft³ it is heavier than 46% of the 170 species measured — an 8-foot 1×6 board weighs about 12.1 lb.
- Stability: its T/R ratio of 1.92 is more even than 38% of the 196 species here — as humidity changes, 62% of them hold their shape more evenly.
See Sweetgum 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 Sweetgum is unavailable or priced out.
- Black Cherry is a common substitute for Sweetgum : 12% harder, about the same weight, and similarly stable in service.
- Hackberry is a common substitute for Sweetgum : nearly identical hardness, about the same weight, and similarly stable in service.
- Red Maple is a common substitute for Sweetgum : 12% harder, about the same weight, and similarly stable in service.
- Tamarack is a common substitute for Sweetgum : 31% softer, about the same weight, and similarly stable in service.
| Species | Janka | Density | T/R |
|---|---|---|---|
| Black Cherry | 950 lbf | 34.9 | 1.92 |
| Hackberry | 880 lbf | 37 | 1.85 |
| Red Maple | 950 lbf | 37.7 | 2.05 |
| Tamarack | 590 lbf | 37 | 2 |
About Sweetgum
Sweetgum (Liquidambar styraciflua) grows from southwestern Connecticut westward into Missouri and southward to the Gulf Coast. Almost all lumber is produced in the Southern and South Atlantic States. The lumber from sweetgum is usually separated into sap gum (the light-colored sapwood) or redgum (the reddish- brown heartwood). Sweetgum often has a form of cross grain called interlocked grain, and it must be dried slowly. When quartersawn, interlocked grain produces a ribbon-type stripe that is desirable for interior woodwork and furniture. The wood is moderately heavy and hard. It is moderately strong, moderately stiff, and moderately high in shock resistance. Sweetgum is used principally for lumber, veneer, plywood, slack cooperage, railroad crossties, fuel, pulpwood, boxes and crates, furniture, interior molding, and millwork.
Durability & sustainability
Decay resistance: the Wood Handbook rates Sweetgum heartwood slightly or nonresistant 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 Sweetgum.
Properties
| Specific gravity | 0.52 |
|---|---|
| Janka hardness (side) | 850 lbf |
| Density (air-dry, 12% MC) | 36.3 lb/ft³ (581 kg/m³) ovendry-weight basis: 32.4 lb/ft³ |
| Weight per board foot (air-dry) | 3.03 lb |
| Radial shrinkage (green→oven-dry) | 5.3% |
| Tangential shrinkage (green→oven-dry) | 10.2% |
| Volumetric shrinkage (green→oven-dry) | 15.8% |
| T/R ratio (stability indicator) | 1.9 |
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.