Q I started working on one of your recent shelf projects and found some of the measurements confusing. The shelf sides are listed as 1x3s but the Cutting List says the board is 3/4 x 2-1/2 in. So which dimension do I use?
A Sorry for the confusion, but the dimensions are one and the same. Most lumber is sold in “nominal” (in name only) sizes such as 1x3, 2x4 and 4x4. 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). Our Cutting Lists always give the exact dimension of the wood piece.
This handy chart will help you translate the nominal into the actual (dry). After a while, you’ll get the hang of it.
Thickness (inches) |
Width (inches) |
Nominal |
Actual |
Nominal |
Actual |
1 |
3/4 |
2 |
1-1/2 |
1-1/4 |
1 |
3 |
2-1/2 |
1-1/2 |
1-1/4 |
4 |
3-1/2 |
2 |
1-1/2 |
5 |
4-1/2 |
2-1/2 |
2 |
6 |
5-1/2 |
3 |
2-1/2 |
7 |
6-1/2 |
3-1/2 |
3 |
8 |
7-1/4 |
4 |
3-1/2 |
9 |
8-1/4 |
4-1/2 |
4 |
10 |
9-1/4 |
5+ |
1/2" less |
11-16 |
3/4" less |
