2×4 Size – Actual & Nominal Measurements
If you’ve ever bought lumber for a DIY project, you might have noticed something strange — a 2×4 isn’t actually 2 inches by 4 inches. This difference comes from the way lumber is cut and finished. Let’s break down exactly what “2×4 size” means so you’ll always know what you’re working with.
Nominal vs. Actual Size
The term “2×4” is the nominal size. This is the rough-cut size before the wood is dried and planed smooth. Once it’s processed to make it usable for construction, the size becomes smaller — this is called the actual size.
– Nominal Size: 2 inches × 4 inches
– Actual Size: 1.5 inches × 3.5 inches
– Metric Equivalent: 38 mm × 89 mm
2×4 Size Table
| Type | Inches (Actual) | Millimeters (Actual) |
|---|---|---|
| Standard 2×4 | 1.5 × 3.5 | 38 × 89 |
| Green/Unsurfaced 2×4 | 1.75 × 3.75 | 44 × 95 |
International Variations
In countries like Canada and the UK, dimensions can differ slightly due to local milling standards. Always check before purchasing if precision is important for your project.
Common Uses for a 2×4
- Wall studs in framing
- Workbenches
- Furniture projects
- Outdoor garden frames
FAQ – 2×4 Size
Why is a 2×4 not actually 2 inches by 4 inches?
Because the nominal size refers to the lumber’s size before drying and planing. Processing reduces it to the actual size.
What’s the metric size of a 2×4?
Approximately 38 mm × 89 mm for standard kiln-dried lumber.
Do all stores sell the same size 2×4?
Most U.S. stores follow the same standard, but always check if buying in bulk or for precision builds.
Final Tip
If you’re building something where exact measurements matter, always measure the wood yourself before cutting — the “2×4 size” on the label may not match what you expect.