What is the actual size of a 2 x 4 surfaced dry piece of framing lumber?

• A. 2 by 4
• B. 1-3/4 by 3-3/4
• C. 1-1/2 by 3-1/2
• D. 1-1/4 by 3-1/4

Answer: (C)

In framing lumber, the name “2x4” is a rough, nominal size, not the finished dimensions. After the wood is milled (surfaced) and kiln-dried, it shrinks to its actual size. For a common 2x4, the thickness ends up about 1-1/2 inches and the width about 3-1/2 inches. That’s why the actual size is 1-1/2 by 3-1/2 inches. The other options don’t reflect the standard finished dimensions used in framing, which is why they aren’t correct.