Nominal vs actual dimensions
Wood dimension chart
This chart shows the nominal (in name only) and corresponding actual (real) dimensions of common wood sizes.
Note: The chart can be downloaded and printed from Additional Information below.
If you find reading plans 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 and 4×4. But these sizes are not the actual 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 it.