Wood Sizing and Selection Guide

When Andrew and I were building our first piece of DIY furniture, we got frustrated when it seemed like all our cuts were wrong. Andrew had spent hours planning and perfecting our first custom DIY plan and it seemed like all that work was for nothing.

Nothing was fitting together the way it was supposed to. During this frustration and confusion, we found out that boards are not the size they say they are.

The name is based on the rough sizing before the wood is finished at the lumber mill, so your 4×4 isn’t really 4″ by 4″, it’s 3.5″ by 3.5″. That half-inch makes a big difference when you pre-planned all your measurements!

Below’s a guide of the most common board sizes and what their actual size is.

Board Size	Actual Size
1 x 2	.75″ x 1.5″
1 x 4	.75″ x 3.5″
1 x 6	.75″ x 5.5″
1 x 8	.75″ x 7.25″
2 x 2	1.5″ x 1.5″
2 x 4	1.5″ x 3.5″
2 x 6	1.5″ x 5.5″
2 x 8	1.5″ x 7.25″
4 x 4	3.5″ x 3.5″

When you’re going to Home Depot or Lowe’s to pick out wood for a project, not all wood is created equal. Spend some time trying to select good boards. By good boards, I mean a board that is straight and doesn’t have any major imperfections.

You can usually look at a board and tell if it is crooked or bowed, but to make sure, it helps to lay the board on the floor. If it’s lifting like the picture below, keep looking!

Now if you do end up with a bowed board, it’s not the end of the world. Screws are pretty powerful and can generally help correct the warping, but why fix something when you could try to avoid the issue in the first place?

To double-check if a board is crooked, you can put it against a board that you think looks pretty straight. This will help you visualize just how crooked the board is.

The last major thing to check for when selecting wood is noticeable imperfections. This can be big deposits of sap or rough edges and corners. In the examples below, you will want to steer clear of imperfections like the one on the left.

The one on the right could be filled with stainable wood putty, but I have yet to find a wood putty that actually ends up blending into the wood after staining. So, my recommendation is to avoid both examples if possible.

To sum it all up, remember that board names are not reflective of their true size. We’ve accounted for this in all of our plans, but if you’re making adjustments or plans of your own, refer back to the table.

When selecting wood, be picky. Avoid bowed boards, crooked boards, and boards with noticeable imperfections.

Now that you are a wood selecting expert, let’s start DIYing! See all of our DIY  posts.