What are the actual dimensions of a standard 2 x 4 after surfacing?

What are the actual dimensions of a standard 2 x 4 after surfacing?

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

Answer: (B)

Lumber is sold by nominal sizes, but the actual cross-section is smaller after surfacing. When a 2x4 is planed smooth, material is removed from both faces, typically reducing thickness from 2 inches to 1-1/2 inches and width from 4 inches to 3-1/2 inches. That gives the standard dressed size of 1-1/2 by 3-1/2 inches. So the best answer reflects these actual dimensions after milling. The other options describe the rough or nonstandard dimensions and don’t match the dressed size you’d use in framing.

Lumber is sold by nominal sizes, but the actual cross-section is smaller after surfacing. When a 2x4 is planed smooth, material is removed from both faces, typically reducing thickness from 2 inches to 1-1/2 inches and width from 4 inches to 3-1/2 inches. That gives the standard dressed size of 1-1/2 by 3-1/2 inches. So the best answer reflects these actual dimensions after milling. The other options describe the rough or nonstandard dimensions and don’t match the dressed size you’d use in framing.