2x4 Actual Size

The real dimensions of a nominal 2x4, and what it's commonly used for.

MeasurementValue
Nominal size2x4
Actual thickness1-1/2"
Actual width3-1/2"
Board feet per linear foot0.667
Approx. weight per linear foot1.42 lb (kiln-dried softwood)
Common usesWall studs, framing, furring

Why a 2x4 measures 1-1/2" × 3-1/2"

Like all dimensional lumber, a 2x4 starts life close to its nominal size before it's dried and planed smooth on all four sides. That process removes roughly 1/2 inch from each dimension, leaving the actual, finished size you buy at 1-1/2" × 3-1/2". This is standard across every softwood lumberyard in the US, not specific to any one supplier.

Where these numbers come from

Actual dimensions reflect the American Softwood Lumber Standard (PS 20) size for surfaced dry (S-DRY) dimension lumber. Weight is an approximate figure for kiln-dried softwood framing lumber and varies somewhat by species and moisture content.

Frequently asked questions

Is a 2x4 really 2 by 4 inches?

No -- like all dimensional lumber, the 2x4 name describes the rough size before milling. After drying and planing, the actual size is 1-1/2" × 3-1/2".

Does this size vary by species?

The actual dimension is standardized across species for a given nominal size, though weight per linear foot varies somewhat since different softwood species have different densities.

What is a 2x4 commonly used for?

Wall studs, framing, furring.

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