Dimensional Lumber Sizes report
Dimensional lumber is wood that has been cut and planed to standard widths and heights, while lengths vary for different building frames. The law requires workshops to use the exact standard measurements for dimensional lumber so that consumers know what actual size they need when purchasing. In the United States, common dimensional lumber sizes include 2 inches x 4 inches and 2 x 6 inches.
The lumberyard divides materials into broad categories to help organize and categorize them. While standard terms used to refer to dimensional lumbers may be considered to be their actual size, this is not the case. These measurements refer to the dimensions of the lumber in the "rough" state before shrinking during drying and planning. Therefore, the actual size of the dimensional lumber is slightly smaller than the marked numbers you see.
Both hardwood and softwood can be used as dimensional lumber. Generally speaking, cork is less expensive. If your project calls for precise measurements, be sure to check your lumber before purchasing. The following post explains common dimensional lumber sizes.
Dimensional Lumber Size Guide
The term dimensional lumber refers to softwood species (such as pine or fir) used in the building frame and other carpentry uses. Softwood lumber is generally used for framing walls and floors. In the United States, softwood lumber is governed by the National Institute of Standards American Softwood Lumber Standard.
Nominal size is an easy way to remember it. The actual size is as real as if you were using a tape measure or a straight edge to measure the dimensions of the stock. The actual size is anywhere from 1/4 inch to 3/4 inch less than the nominal size. Even experienced woodworkers may find it difficult to remember the difference between nominal and actual dimensions.
Nominal vs. Actual Measurements of Dimensional Lumber
Dimensional lumber is cut to a specific length, width, and depth. However, there is a difference between the nominal and actual sizes. The tables below provide the nominal and actual lumber dimensions for many common North American lumbers.
| Nominal Size | Actual Size(inch) | Actual Size(mm) |
|---|---|---|
| 1 x 2 | 3/4 x 1 1/2 inches | 19 x 38 mm |
| 1 x 3 | 3/4 x 2 1/2 inches | 19 x 64 mm |
| 1 x 4 | 3/4 x 3 1/2 inches | 19 x 89 mm |
| 1 x 6 | 3/4 x 5 1/2 inches | 19 x 140 mm |
| 1 x 8 | 3/4 x 7 1/4 inches | 19 x 184 mm |
| 1 x 10 | 3/4 x 9 1/4 inches | 19 x 235 mm |
| 1 x 12 | 3/4 x 11 1/4 inches | 19 x 286 mm |
| 2 x 2 | 1 1/2 x 1 1/2 inches | 38 x 38 mm |
| 2 x 3 | 1 1/2 x 2 1/2 inches | 38 x 64 mm |
| 2 x 4 | 1 1/2 x 3 1/2 inches | 38 x 89 mm |
| 2 x 6 | 1 1/2 x 5 1/2 inches | 38 x 140 mm |
| 2 x 8 | 1 1/2 x 7 1/4 inches | 38 x 184 mm |
| 2 x 10 | 1 1/2 x 9 1/4 inches | 38 x 235 mm |
| 2 x 12 | 1 1/2 x 11 1/4 inches | 38 x 235 mm |
| 4 x 4 | 3 1/2 x 3 1/2 inches | 89 x 89 mm |
| 4 x 6 | 3 1/2 x 5 1/2 inches | 89 x 140 mm |
| 4 x 8 | 3 1/2 x 7 1/4 inches | 89 x 184 mm |
| 4 x 10 | 3 1/2 x 9 1/4 inches | 89 x 235 mm |
| 4 x 12 | 3 1/2 x 11 1/4 inches | 89 x 286 mm |
| 6 x 6 | 5 1/2 x 5 1/2 inches | 140 x 140 mm |
| 8 x 8 | 7 1/4 x 7 1/4 inches | 184 x 184 mm |
Conclusion
Remember to take a tape measure and head over to the dimensional lumber aisles. Measure the actual width and thickness of lumber, and then look at the sign above the rack. In most cases, hardwood lumbers come in random widths. However, in some cases, like the big-box hardware stores, the lumbers come in dimensional widths similar to softwood widths. It is advisable to check with your contractor or lumber supplier before finalizing design details.
