What Is The Actual Size Of A 1x10 Board

Yous may have seen framing lumber and softwood boards sold at your local lumber one thousand or hardware store advertised using dimensions that don't match the actual size of the board. Hopefully y'all oasis't been burned by assuming that a 2 x 4 is actually 2 inches past 4 inches simply if you have, know that yous're not alone.

You lot might be wondering "what's the deal?" Why is lumber advertised using dimensions that are inaccurate?

Believe information technology or non, this is not an error at the manufactory or a big corporation trying to take advantage of y'all, and in that location is actually a reason for this.

Actual Size of Dimensional Lumber

Most softwood lumber sold at the lumber one thousand is dimensional lumber. Dimensional lumber is lumber that has been dried and milled to standard dimensions and is well-nigh commonly used for framing and construction.

Dimensional lumber is sold using what is referred to as the nominal dimensions of a board. These are the dimensions of the lath before it'due south been stale and milled. The actual sizes of a board are smaller than that.

For case, a 2 ten 4 board is really i 1/2″ x 3 one/2″. The lath is advertised and sold using the nominal dimensions, which are a bit larger than the bodily size.

Refer to the table below to see the actual size of lumber.

Table showing the nominal size and bodily size of dimensional lumber in inches and millimeters
Nominal Size	Bodily Size (inches)	Actual Size (mm)
ane 10 two	3/4″ x 1 ane/ii″	19 mm x 38 mm
1 10 4	iii/4″ x 3 one/two″	19 mm x 89 mm
ane x 6	iii/4″ x 5 1/2″	nineteen mm x 140 mm
1 ten eight	3/4″ 10 seven 1/4″	xix mm x 235 mm
one ten ten	3/four″ x 9 1/iv″	xix mm x 235 mm
ane 10 12	3/4″ x xi i/4″	19 mm x 286 mm
ii ten two	1 1/2″ x one ane/2″	38 mm ten 38 mm
2 10 iv	1 1/2″ x 3 one/2″	38 mm x 89 mm
2 ten 6	i ane/two″ x v 1/2″	38 mm x 140 mm
2 x 8	1 1/ii″ x 7 1/4″	38 mm x 184 mm
2 10 10	1 1/two″ 10 9 1/4″	38 mm x 235 mm
2 x 12	ane 1/2″ ten 11 one/4″	38 mm ten 286 mm
4 x 4	3 1/2″ ten 3 1/2″	89 mm x 89 mm
4 x 6	3 1/two″ 10 5 1/2″	89 mm 10 140 mm

If you lot're stuck without a tape measure or reference table yous tin too use a simple rule of pollex to determine the actual size of dimensional lumber.

If the nominal size is smaller than one" then the actual size is ane/four" smaller than the nominal size.
If the nominal size is larger than 2" and smaller than eight" and so the actual size is one/2" smaller than the nominal size.
If the nominal size is 8" or larger, then the bodily size of the board will exist 3/iv" smaller.

Why is dimensional lumber smaller than the nominal dimensions?

Historically, softwood logs were cutting light-green into 2×4 simply would naturally shrink as the boards dried out, and after planing and milling, they ended upwardly around 1.v×iii.v. Today, boards are intentionally cutting big to permit for shrinkage during kiln drying and the milling process.

Because the amount a lath shrinks can vary by wood species, moisture content, and even the private tree, the concluding size may vary slightly. Modern sawmills typically account for this, yet, and dimensional lumber is more often than not pretty consistent.

Bonus: Hardwood Lumber Sizes & Dimensions

Hardwood lumber is sold very differently from dimensional lumber and is ordinarily measured by the board foot. Computing lath feet can exist a little tricky, merely it's essentially simply a measurement of the volume of the board.

Hardwood lumber is often sized past the thickness of the board, which is measured in quarters rather than inches. Quarters refer to the number of quarters of an inch of lath thickness. For instance, a one" thick lath is referred to as 4/4.

To brand things more confusing, hardwood lumber is also sold either rough sawn or surfaced on one, two, three, or all four sides. Boards that have been surfaced are referred to using the designations S1S, S2S, S3S, or S4S, depending on how many surfaces have been planed.

These designations are important since they impact the actual thickness of a board. For example, a 4/4 board is 1" thick when information technology'south purchased rough, only is seven/8" thick after surfacing one side and is 13/sixteen" thick subsequently surfacing two sides. Refer to the tabular array below to see the thicknesses of hardwood lumber that is crude or surfaced.

Table showing the nominal and actual thicknesses of hardwood lumber
Nominal Size	Rough Size (inches)	S1S Actual Size (inches)	S2S Actual Size (inches)
–	1/2″	3/8″	5/sixteen″
–	5/8″	one/2″	vii/xvi″
–	three/four″	5/eight″	ix/xvi″
4/iv	1″	7/eight″	13/16″
5/4	1 1/4″	i 1/viii″	one i/16″
vi/4	1 1/2″	i three/8″	1 5/16″
8/4	2″	one xiii/16″	one 3/iv″
12/four	3″	2 13/16″	2 3/4″