Actual dimensions of 1 x 1 lumber are 3/4 x 3/4 (19.05 x 19.05 mm). In fact, it’s smaller than what the nominal measurements indicate. Nevertheless, hardware stores call it 1-by-1 lumber despite the incorrect nominal size due to the standard measurement.
Logs that are sawn from trees are rough and have rough edges. Home Depot and other local hardware stores sell lumber that has smoothed and planned edges.
A 1×1 board has the same length regardless of its actual or nominal size. For example, an 8 feet long board will have an 8 feet actual length, the same is true with other sizes such as 6 feet, 10 feet, 4 feet, etc.
In order to find out the exact dimensions, it’s best to do some quick measurements.
1×1 lumber dimensions
| 1×1 lumber | Nominal size in inches | Actual size in inches |
| Width | 1 Width | 3/4 |
| Height | 1 length | 3/4 |
| 1×1 Lumber | Nominal size in mm | Actual size in mm |
| Width | 25.4 | 19.05 |
| Height | 25.4 | 19.05 |
Lumber has two different sizes. Actual vs Nominal. Actual size is what the exact measurement of the lumber would be now, the Nominal size is
Why is the actual size of a 1 x 1 lumber smaller than its nominal size?
Typically, a plank is measured as it is in its original shape, but the lumber we purchase has been smoothened during the manufacturing process. This process results in the board shrinking.
Timber that is still green or fresh has a rough surface. In order to smooth out the surface of timber, it is put through a planer on both sides so that it has a uniform thickness. As thin layers of timber are sliced away during planning, its thickness shrinks, resulting in a thin edge. Timbers with smooth surfaces on all four sides generally lose thickness and width, resulting in a smaller size.
