Most people are confused about wood board measurements and end up buying the wrong size. For instance, DIYers end up confused with the actual size of 2×6 lumber as it is smaller than they expected.
Contrary to what the name suggests, its actual size can be surprisingly different from what one might anticipate. So, to help you make informed decisions for your next project, here’s a guide that will demystify 2×6 lumber dimensions.
Actual Dimensions of a 2×6 Lumber
The actual dimension of 2×6 inches measures 1 1/2 x 5 1/2 inches or 38×140 mm. The latter is the real measurement of the lumber despite its nominal dimensions of 2×6 inches.
Millers and manufacturers use nominal dimensions to indicate the dimension of the original wood plank.
But for practical applications, you should know the actual dimension of the lumber, especially when used for constructing houses and apartments or even simple household projects.
So how does a 2×6 lumber become smaller in its actual size? The processing method of wood reduces its size to match the measurement requirements of woodworkers.
The wood processing explains the marketed size or nominal dimension of wood lumber, which does not match the actual measurement.
Actual Measurements of Dimensional Lumber
When we say dimensional size, we refer to it as the depth and width of lumber. Although the length does not include dimensional size, you must consider the length as a vital part of dimensional lumber.
Typically, the thickness and length of wood depend on how you will use the dimensional lumber. So, you need dimensional lumber for structural elements or framing support for your residential home and various construction projects.
Basic Lumber Sizing
Basic lumber sizing involves the depth and width of lumber. In the nominal size of 2×6 inches, the numerical 2 stands for the depth and 6 inches is the width.
Sometimes, you can find dimensional lumber with marketed size labeled as depth x width x length. At first, you will be confused again by the third number which stands for the length of lumber.
But later on, the length in the nominal size of dimensional lumber will give you an idea of your wood requirement. You can still get the same length as the original wood slab even if it was a finished product or already processed.
So, if the nominal size is 2x6x10, you can now understand that the numerical stands for DxWxL. Again, the actual size of depth and width are smaller than the marketed or nominal size.
Nominal vs. Actual Sizes
Throughout this article, I’ve touched on the distinction between nominal and actual sizes of lumber. To drive the point home: you simply can’t interchange these measurements.
So, we will give you the main reason why the two have no similarities at all.
Nominal Size
The nominal measurement is the original size of the lumber before it’s cut into different sizes. The measurement stands for the depth and width of lumber.
Actual Size
Meanwhile, the real size of 2×6 lumber is the precise measurement of the wood after it was dried and planed. Due to this process, the dimension of the wood slab changed drastically from its texture and size.
The importance of inquiring about the actual size of the lumber prevents inaccuracy of wood materials in your house improvements and wood projects.
Do Nominal and Actual Sizes Ever Match?
From my experience, the nominal size has not matched the actual size of wood lumber. Aside from 2×6 lumber, the nominal sizes of thinner or thicker dimensional lumber will never match the actual size.
But you can reduce 4×4 lumber by sawing or cutting it to the size of 2×6 lumber which is 1 1/2 x 5 1/2 inches. Just make sure that the lumber is still in good condition.
Sizes for Different Materials
When purchasing wood materials, you should understand that there are different types of wood including their sizes.
Plywood and Other Sheets
Plywood is the finished wood product after manufacturers glued three or more wood veneers. The standard sizes of plywood are 4 ft. x 8 ft., 4 ft x 9 ft, and 4 ft by 4 ft.
Then you can choose the plygrade or thickness of plywood to meet the standard requirement of your wood projects.
For instance, you can choose from a 3-ply with a thickness that measures 1/8 inch or 4mm. If you’re going to have the 5-ply, the thickness should be 1/2 inch or 6.5mm. But if you are looking for exterior purposes such as roofing, you should purchase the multi-ply.
To elaborate, multi-ply is composed of 7 to 21 layers of veneers. This type of plywood is strong and can withstand wind and damage. The thickness should start from 3/4 inch or 9mm for 7 layers to 1 inch or 30 mm for 21 layers.
Also, depending on the finish, plywood is graded A, B, C, or D with A being the smoothest sanded finish. You can also purchase plywood with a different finished grade on both sides.
Hardwood Lumber Length
It is also important to note the standard length of hardwood lumber. Unlike the dimensions, the length of the lumber remains almost the same. You can choose from 8 feet, 10 feet, 12 feet, 14 feet, 16 feet, going up to 24 feet.
Hardwood Lumber Dimensions
Woodworkers rely on the thickness of lumber to know its durability. But the nominal thickness of hardwood lumber depends on the surface on one side (S1S) or two sides (S2S).
| Nominal Thickness | Actual Size – S1S | Actual Size – S2S |
| 1/2 inch | 3/8 inch (9.5 mm) | 5/16 inch (7.9mm) |
| 5/8 inch | 1/2 inch (13 mm) | 7/16 inch (11 mm) |
| 3/4 inch | 5/8 inch (16 mm) | 9/16 inch (14 mm) |
| 1 (4/4) inch | 7/8 inch (22 mm) | 13/16 inch (21 mm) |
| 1 1/4 (5/4) inches | 1 1/8 inches (29 mm) | 1 1/6 inches (27 mm) |
| 1 1/2 (6/4) inches | 1 3/8 inches (35 mm) | 1 5/16 inches (33 mm) |
| 2 (8/4) inches | 1 13/16 inches (46 mm) | 1 3/4 inches (44 mm) |
| 3 (12/4) inches | 2 13/16 inches (71 mm) | 2 3/4 inches (70 mm) |
| 4 (16/4) inches | 3 13/16 inches (97 mm) | 3 3/4 inches (95 mm) |
Quarter System
The quarter system of hardwood lumber refers to the actual thickness of the wood log. This method is commonly used by mills when selling rough lumber. The thickness equivalent of 4/4 is 1 inch, 6/4 is 1 1/2 inches and 8/4 is 2 inches.
Board Foot
One board foot is almost the size of lumber 12 inches long, 12 inches wide, and 1 inch thick (12x12x1). Millers and lumber suppliers use board sizes like 1×4, 1×6, 2×4, and 2×6 to label the actual amount of wood they need from a wood plank.
Glue-Laminated Lumber
Glue-laminated lumber or glulam has more durability and greater strength using the strongest laminations [1]. Glulam offers various benefits, including improved resistance to warping, shrinking, and splitting.
This lumber is the superior choice for house construction, building bridges, and other major structures. You can increase design values and create different sizes of lumber dimensions.
Softwood Lumber Dimensions
Softwood lumber dimensions have nominal sizes of 1”, 2”, 3”, 4”, 6”, and 8” but its actual thickness is smaller.
The actual thickness of 1×2 inches is equivalent to 3/4 x 1 1/2 inches. 2” is 1 1/2 inches, 3” is 2 1/2 inches, 4” is 3 1/2 inches, 4” is 3 1/2 inches, 6” is 5 1/2 inches, and 8” is 7 1/4 inches.
Softwood Lumber Length
Like other sizes of wood materials, softwood lumber length has a sizing standard. The thickness and width generally span from 6 inches up to 24 inches. And between these sizes, you’ll find consistent 2-inch variations.
FAQ
What is the Maximum Size of a 2×6 Board?
The board measuring 2×6 will lose almost half an inch in thickness and 1/2 inch in width before leaving the mill or wood manufacturers. Meaning, the maximum size of a 2×6 board is 1 1/2 inches x 5 1/2 inches in actual measurement.
When looking for the accurate size of a 2×6 board, you need to inquire about the actual measurement of each wood lumber.
Conclusion
Do not be confused with the actual size of 2×6 lumber when buying a piece or two. The marketed size never matches the actual size and that is a fact.
So, knowing the actual measurements of dimensional lumber gives you the upper hand, like professional woodworkers, in terms of precise measurements.
Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.
Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
