Reference tables
Sizes, densities and movement, in one place
The datasets the calculators use, plus metric lumber, screw and nail size charts, with the issuing body, table number and verification date for each.
Lumber and fastener size charts
PS 20 · USDA FPL Wood Handbook · AWC NDS- Lumber sizes in mm
1x2 to 2x12, 4x4 and 6x6: nominal label, actual dressed size in inches and millimetres, and dry and green minimums from PS 20.
- Screw size chart
Wood screw gauges #4 to #20: shank, root and head diameters, pilot and shank holes, penetration and metric equivalents.
- Nail size chart
Penny sizes 3d to 60d: lengths, common, box and sinker nail diameters and wire gauges, and how deep to nail.
Nominal vs dressed softwood
PS 20-20 Table 3 · North America| Nominal | Class | Dressed (in) | Dressed (mm) |
|---|---|---|---|
| 1×2 | Boards | ¾ × 1½ | 19 × 38 |
| 1×3 | Boards | ¾ × 2½ | 19 × 64 |
| 1×4 | Boards | ¾ × 3½ | 19 × 89 |
| 1×6 | Boards | ¾ × 5½ | 19 × 140 |
| 1×8 | Boards | ¾ × 7¼ | 19 × 184 |
| 2×2 | Dimension | 1½ × 1½ | 38 × 38 |
| 2×4 | Dimension | 1½ × 3½ | 38 × 89 |
| 2×6 | Dimension | 1½ × 5½ | 38 × 140 |
| 2×8 | Dimension | 1½ × 7¼ | 38 × 184 |
| 2×10 | Dimension | 1½ × 9¼ | 38 × 235 |
| 2×12 | Dimension | 1½ × 11¼ | 38 × 286 |
Minimum dressed dry sizes. Actual stock varies by species, moisture, mill and supplier; measure for precise work.
Source
Voluntary Product Standard PS 20-20: American Softwood Lumber Standard. U.S. Department of Commerce, National Institute of Standards and Technology, PS 20-20 Revision 1, October 2021. Table 3 minimum dressed dry thicknesses and widths for the Boards and Dimension classifications. Millimetres are converted at 25.4 mm per inch and rounded. Verified .
Species density at 12% MC
USDA FPL Wood Handbook| Species | SG at 12% | kg/m³ | lb/ft³ |
|---|---|---|---|
| Western redcedar | 0.32 | 358 | 22.4 |
| Ponderosa pine | 0.40 | 448 | 28 |
| Coast Douglas-fir | 0.48 | 538 | 33.6 |
| Black cherry | 0.50 | 560 | 35 |
| Black walnut | 0.55 | 616 | 38.5 |
| Northern red oak | 0.63 | 706 | 44 |
| White oak | 0.68 | 762 | 47.5 |
| Sugar maple | 0.63 | 706 | 44 |
| Red maple | 0.54 | 605 | 37.8 |
| Yellow birch | 0.62 | 694 | 43.3 |
| White ash | 0.60 | 672 | 42 |
Source
Wood Handbook—Wood as an Engineering Material, Chapter 5: Mechanical Properties of Wood. USDA Forest Service, Forest Products Laboratory, Revised 2021. Table 5-3a mean specific gravity based on oven-dry mass and volume at 12% moisture content. Verified .
Wood Handbook—Wood as an Engineering Material, Chapter 4: Moisture Relations and Physical Properties of Wood. USDA Forest Service, Forest Products Laboratory, Revised 2021. Equation 4-14: density at moisture content x equals Gx multiplied by water density and (1 + x/100). Pounds per cubic foot are converted at 16.0185 kg/m³ per lb/ft³. Verified .
Shrinkage, green to ovendry
USDA FPL Wood Handbook| Species | Radial % | Tangential % |
|---|---|---|
| Western redcedar | 2.4 | 5 |
| Ponderosa pine | 3.9 | 6.2 |
| Coast Douglas-fir | 4.8 | 7.6 |
| Black cherry | 3.7 | 7.1 |
| Black walnut | 5.5 | 7.8 |
| Northern red oak | 4 | 8.6 |
| White oak | 5.6 | 10.5 |
| Sugar maple | 4.8 | 9.9 |
| Red maple | 4 | 8.2 |
| Yellow birch | 7.3 | 9.5 |
| White ash | 4.9 | 7.8 |
Source
Wood Handbook—Wood as an Engineering Material, Chapter 4: Moisture Relations and Physical Properties of Wood. USDA Forest Service, Forest Products Laboratory, Revised 2021. Table 4-3, shrinkage values for domestic woods. Total shrinkage from green to ovendry, expressed as a percentage of the green dimension. Verified .