2x4 Actual Size
Find the actual thickness, width, and metric dimensions of commonly sold 2x4 lumber.
2x4 Lumber Dimensions
| Nominal Size | 2 × 4 in |
|---|---|
| Actual Thickness | 1.5 in |
| Actual Width | 3.5 in |
| Metric Size | 38 × 89 mm |
What Is the Actual Size of a 2x4?
The actual finished dimensions of a commonly sold dry 2x4 are approximately 1.5 inches thick and 3.5 inches wide.
The name 2x4 is the nominal size used to identify the lumber. The finished dimensions are smaller than the nominal dimensions.
Why Is a 2x4 Not Actually 2x4?
Lumber is commonly identified using nominal dimensions. During manufacturing, rough-sawn lumber is dried and surfaced, which reduces its finished dimensions.
As a result, the nominal 2x4 designation does not describe the final measured thickness and width of a typical finished board.
Learn more on our Nominal vs. Actual Lumber page.
2x4 Size in Millimeters
A commonly sold 2x4 has an actual reference size of approximately 38 × 89 mm.
The metric dimensions are a conversion of the actual lumber dimensions rather than a direct conversion of the nominal 2 × 4 designation.
See the complete lumber sizes in millimeters reference.
Common Uses of 2x4 Lumber
2x4 lumber is commonly used for residential construction, framing, interior walls, partitions, and a wide range of DIY and woodworking projects.
Related Lumber Sizes
2x4 FAQ
Is a 2x4 actually 2 inches by 4 inches?
No. A commonly sold dry 2x4 has an actual finished size of approximately 1.5 by 3.5 inches.
What is a 2x4 in mm?
The common actual reference dimension is approximately 38 × 89 mm.
What is the thickness of a 2x4?
The common actual finished thickness is approximately 1.5 inches.