Lumber Dimensions Converter
Look up actual versus nominal lumber dimensions for 1x2 through 6x6.
A 2x4 is actually 1.5 in x 3.5 in after drying and milling — with mm equivalents.
Select a nominal lumber size to see actual dimensions, or calculate board feet below.
In North America, lumber is sold by nominal size, but the actual dimensions are smaller. This is because wood shrinks when dried and is planed smooth after cutting.
Standard softwood lumber (dry, dressed):
| Nominal (in) | Actual (in) | Actual (mm) |
|---|---|---|
| 1 × 2 | 0.75 × 1.5 | 19 × 38 |
| 1 × 4 | 0.75 × 3.5 | 19 × 89 |
| 1 × 6 | 0.75 × 5.5 | 19 × 140 |
| 1 × 8 | 0.75 × 7.25 | 19 × 184 |
| 1 × 10 | 0.75 × 9.25 | 19 × 235 |
| 1 × 12 | 0.75 × 11.25 | 19 × 286 |
| 2 × 2 | 1.5 × 1.5 | 38 × 38 |
| 2 × 4 | 1.5 × 3.5 | 38 × 89 |
| 2 × 6 | 1.5 × 5.5 | 38 × 140 |
| 2 × 8 | 1.5 × 7.25 | 38 × 184 |
| 2 × 10 | 1.5 × 9.25 | 38 × 235 |
| 2 × 12 | 1.5 × 11.25 | 38 × 286 |
| 4 × 4 | 3.5 × 3.5 | 89 × 89 |
| 4 × 6 | 3.5 × 5.5 | 89 × 140 |
| 6 × 6 | 5.5 × 5.5 | 140 × 140 |
Board Feet: Board feet is the standard unit for purchasing hardwood lumber.
- 1 board foot = 1 inch thick × 12 inches wide × 12 inches long
- Board feet = (thickness_in × width_in × length_in) ÷ 144
Metric countries sell lumber by actual dimensions in millimeters.