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Making Sense of Lumber Dimensions

Updated: Jan. 18, 2023

The difference between “nominal” and “actual” dimensions for items like 2x4 dimensions

Lumber sizes 1x4 lumber 2x4 actual size dimensionsFamily Handyman
Don't be confused by nominal board dimensions when you buy lumber or read plans. We show you the quick translation to actual numbers, including 2x4.

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Nominal vs. actual for wood with 2×4 dimensions

2x4 dimensions 2x6 dimensions 2x2 lumber wood board sizes

Wood dimension chart

This chart shows the nominal (in name only) and corresponding actual (real) dimensions of common wood sizes like 2×4 dimensions and 1×4 lumber.

Note: The chart can be downloaded and printed from Additional Information below.

If you find reading plans and wood board sizes confusing or have trouble identifying the exact dimensions of wood at a lumberyard or home center, read on. Most lumber is sold in “nominal” (in name only) sizes such as 1×3, 2×4, 4×4 and2x2 lumber. But these sizes are not the actual 1×3 dimensions, 2×4 dimensions, 2×6 dimensions, 2×8 dimensions and 4×4 dimensions of the wood. The chart below shows the actual dimensions of lumber when it is dry (when wet, it will be slightly larger). This handy chart will help you translate the nominal into the actual (dry). After a while, you’ll get the hang of dimensional lumber sizes what 2 by 4 actual dimensions means, and it will help for projects like building a deck.

Additional Information About Lumber Sizes