Post Oak wood movement, board-foot & weight calculator
- Janka
- 1,360lbf
- Density
- 46.8lb/ft³
- T/R ratio
- 1.8
- Spec. gravity
- 0.67
Post Oak is a North American hardwood. It has a Janka side hardness of 1,360 lbf, a specific gravity of 0.67, and an air-dry density near 47 lb/ft³ (750 kg/m³) (mechanical values at 12% moisture content). It shrinks 9.8% tangentially and 5.4% radially from green to oven-dry (T/R ratio 1.8), 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 Post Oak: movement, weight & board footage
Every number below is worked from Post Oak'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″ | 0.039″ (≈ 1/32 in) | 0.022″ (≈ 1/32 in) |
| 3″ | 0.059″ (≈ 1/16 in) | 0.032″ (≈ 1/32 in) |
| 4″ | 0.078″ (≈ 3/32 in) | 0.043″ (≈ 1/32 in) |
| 6″ | 0.118″ (≈ 1/8 in) | 0.065″ (≈ 1/16 in) |
| 8″ | 0.157″ (≈ 5/32 in) | 0.086″ (≈ 3/32 in) |
| 10″ | 0.196″ (≈ 3/16 in) | 0.108″ (≈ 3/32 in) |
| 12″ | 0.235″ (≈ 1/4 in) | 0.13″ (≈ 1/8 in) |
| 16″ | 0.314″ (≈ 5/16 in) | 0.173″ (≈ 3/16 in) |
Need a different width or moisture swing? Run the movement calculator preloaded with Post Oak. At a T/R ratio of 1.81, Post Oak 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 | 10.4 lb |
| 1×6 × 8′ | 4 bd ft | 15.6 lb |
| 1×8 × 8′ | 5.33 bd ft | 20.8 lb |
| 1×10 × 8′ | 6.67 bd ft | 26 lb |
| 1×12 × 8′ | 8 bd ft | 31.2 lb |
| 2×4 × 8′ | 5.33 bd ft | 20.8 lb |
| 2×6 × 8′ | 8 bd ft | 31.2 lb |
| 2×8 × 8′ | 10.67 bd ft | 41.6 lb |
Different length or size? Run the board foot calculator or the weight calculator, both preloaded with Post Oak.
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 | 0.18″ (≈ 3/16 in) |
| Chicago, IL | May · 12.3% | Dec · 15.1% | 2.8 pts | 0.11″ (≈ 1/8 in) |
| Miami, FL | Apr · 12.2% | Sep · 14.4% | 2.2 pts | 0.086″ (≈ 3/32 in) |
| Boston, MA | Apr · 11.5% | Sep · 12.8% | 1.3 pts | 0.051″ (≈ 1/16 in) |
| Denver, CO | Jul · 8% | Dec · 10.5% | 2.5 pts | 0.098″ (≈ 3/32 in) |
| Seattle, WA | Jul · 12% | Dec · 16.9% | 4.9 pts | 0.192″ (≈ 3/16 in) |
Driven by Post Oak's tangential shrinkage of 9.8%. These are outdoor equilibrium-moisture figures, so they are an upper bound — a climate-controlled interior swings less. How this is calculated.
How Post Oak compares
Ranked against the 196 species in the Wood Handbook tables this site carries.
- Hardness: at 1,360 lbf, Post Oak is harder than 70% of the 157 species with a Janka figure.
- Weight: at 46.8 lb/ft³ it is heavier than 79% of the 170 species measured — an 8-foot 1×6 board weighs about 15.6 lb.
- Stability: its T/R ratio of 1.81 is more even than 52% of the 196 species here — as humidity changes, 48% of them hold their shape more evenly.
See Post Oak 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 Post Oak is unavailable or priced out.
- White Oak is a common substitute for Post Oak : nearly identical hardness, about the same weight, and similarly stable in service.
- Bur Oak is a common substitute for Post Oak : nearly identical hardness, about the same weight, and similarly stable in service.
- Pecan Hickory is a common substitute for Post Oak : 34% harder, about the same weight, and similarly stable in service.
- Sugar Maple is a common substitute for Post Oak : nearly identical hardness, about the same weight, and less stable in service.
| Species | Janka | Density | T/R |
|---|---|---|---|
| White Oak | 1,360 lbf | 47.5 | 1.88 |
| Bur Oak | 1,370 lbf | 44.7 | 2 |
| Pecan Hickory | 1,820 lbf | 46.1 | 1.82 |
| Sugar Maple | 1,450 lbf | 44 | 2.06 |
About Post Oak
The Wood Handbook describes Post Oak as part of the Oak (White Oak Group); the account below is of that group, which Post Oak belongs to.
White oak lumber comes chiefly from the South, South Atlantic, and Central States, including the southern Appalachian area. Principal species are white (Quercus alba), chestnut (Q. montana), post (Q. stellata), overcup (Q. lyrata), swamp chestnut (Q. michauxii), bur (Q. macrocarpa), chinkapin (Q. muehlenbergii), and swamp white (Q. bicolor). The sapwood of the white oaks is nearly white and roughly 2 to 5 cm (1 to 2 in.) wide. The heartwood is generally grayish brown. Heartwood pores are usually plugged with tyloses, which tend to make the wood impenetrable to liquids. Consequently, most white oaks are suitable for tight cooperage, although many heartwood pores of chestnut oak lack tyloses. The wood of white oak is somewhat heavier than the wood of red oak. Its heartwood has good decay resistance. White oaks are usually cut into lumber, railroad crossties, cooperage, mine timbers, fence posts, veneer, fuelwood, and many other products. High-quality white oak is especially sought for tight cooperage. An important use of white oak is for planking and bent parts of ships and boats; heartwood is often specified because of its decay resistance. White oak is also used for furniture, flooring, pallets, agricultural implements, railroad cars, truck floors, furniture, doors, and millwork.
Durability & sustainability
CITES status: not listed on any CITES Appendix — no international-trade restriction applies to Post Oak.
Properties
| Specific gravity | 0.67 |
|---|---|
| Janka hardness (side) | 1,360 lbf |
| Density (air-dry, 12% MC) | 46.8 lb/ft³ (750 kg/m³) ovendry-weight basis: 41.8 lb/ft³ |
| Weight per board foot (air-dry) | 3.9 lb |
| Radial shrinkage (green→oven-dry) | 5.4% |
| Tangential shrinkage (green→oven-dry) | 9.8% |
| Volumetric shrinkage (green→oven-dry) | 16.2% |
| T/R ratio (stability indicator) | 1.8 |
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.