2×4 actual dimensions
1.5 × 3.5 in3.81 × 8.89 cm
A 2×4 actually measures 1 1/2 in × 3 1/2 in (38 × 89 mm). The name is the rough-sawn size; drying and planing remove about 1/2 in.
Measurements
| Sold as | Typical use |
|---|---|
| 92 5/8 in precut stud | 8 ft ceilings with a single bottom and double top plate |
| 104 5/8 in precut stud | 9 ft ceilings |
| 8, 10, 12, 16 ft | General framing |
What to know
The American Softwood Lumber Standard (PS 20) sets the dry dressed size of a nominal 2×4 at 1 1/2 × 3 1/2 in. Pressure-treated and green lumber can be slightly larger when wet.
Questions people ask
Why is a 2×4 not 2 by 4 inches?
Boards are named by their rough-sawn size. Drying shrinks them and planing smooths them, leaving 1 1/2 × 3 1/2 in.
How wide is a 2×4 in mm?
89 mm (3 1/2 in) wide and 38 mm (1 1/2 in) thick.
Related sizes
Sources and method
- American Softwood Lumber Standard, NIST Voluntary Product Standard PS 20
Imperial and metric values are converted with 1 in = 25.4 mm exactly and rounded only for display. Found a mistake? Report it and we will correct the page.