The actual size of 2×3 lumber is around 1 ½ x 2 1⁄2. Which is shorter than the nominal size. Though the nominal size of a 2×3 lumber is incorrect when measured, it’s still referred to as 2-by-3 lumber in local hardware stores.
The nominal or advertised size of a 2×3 lumber is determined when the surfaces are sanded to make the surface smooth, and lighter by reducing the moisture content of the wood. Consequently, a 2×3 lumber’s nominal seems incorrect. Technically the lumber was of the same size at the time of its sawing.
So hardware stores like home depot sell lumber by their nominal size, despite being it’s incorrect.
In spite of this, the length of a 2×3 board remains the same regardless of whether it is nominal or actual. For example, if the nominal length of 2×3 is 6 feet, the actual length will be 6 feet. Similarly, if the nominal length is 8 feet then the actual length would be 8 feet, and so a 12 feet length board will actually be of 12 feet long, the same as the nominal length.
However, it’s better to do some quick measurements to find out the exact length.
2×3 lumber dimensions (Actual vs Nominal)
| 2×3 lumber | Nominal size in inches | Actual size in inches |
| Width | 2 Width | 1 ½ |
| Height | 3 length | 2 1⁄2 |
| 2×3 Lumber | Nominal size in mm | Actual size in mm |
| Width | 50.8 | 38 |
| Height | 76.2 | 64 |
