2×4 Actual Dimensions

A 2×4 does not actually measure 2 by 4 inches. A standard 2×4 is 1.5 inches by 3.5 inches. The “2×4” is the nominal (rough) size before the board is dried and planed smooth.

Nominal Actual size
2×4 1-1/2 x 3-1/2 in
2×6 1-1/2 x 5-1/2 in
2×8 1-1/2 x 7-1/4 in
2×10 1-1/2 x 9-1/4 in
2×12 1-1/2 x 11-1/4 in
Where the size goes. The board starts at the full nominal size when rough-sawn, then loses material when it is surfaced smooth and dried. Boards 8 in and wider lose 3/4 in instead of 1/2 in.

See the full Lumber Dimensions Chart and Plywood Sizes Chart.

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