What are the nominal dimensions of lumber
Andrew Campbell
Published Mar 19, 2026
Nominal SizeActual Size2 x 61 1/2 x 5 1/2 inches (38 x 140 mm)2 x 81 1/2 x 7 1/4 inches (38 x 184 mm)2 x 101 1/2 x 9 1/4 inches (38 x 235 mm)2 x 121 1/2 x 11 1/4 inches (38 x 286 mm)
What are the dimensions of dimensional lumber?
Technically, dimension lumber is defined as sawed softwood lumber from 2 to 5 inches (5 to 12.7 centimeters) thick and from 4 to 12 inches (10.2 to 30.5 centimeters) wide. The length of dimension lumber can range from 6 to 24 feet.
What is the nominal thickness of the lumber?
Nominal SizeRough SizeActual Size: Surfaced 2 Sides6/4 inch1 1/2 inch1 5/16 inch (33 mm)8/4 inch2 inches1 3/4 inch (44 mm)12/4 inch3 inches2 3/4 inch (70 mm)16/4 inch4 inches3 3/4 inch (95 mm)
Why does lumber have nominal dimensions?
The “nominal” cross-section dimensions of a piece of lumber, such as 2 X 4 or 1 X 6, are always somewhat larger than the actual, or dressed, dimensions. … The reason is that dressed lumber has been surfaced or planed smooth on four sides (called S4S). The nominal measurement is made before the lumber is surfaced.What is the difference between nominal and dimensional lumber?
Softwood nominal dimensions include length and thickness, while hardwood nominal dimensions are for thickness only. Actual thickness size depends on whether the board has been planed on one (S1S) or both (S2S) sides.
When did lumber become nominal size?
Early concepts called for rough lumber to be of full nominal size, often in the dry condition. After World War I, the increasing demand for construction lumber led to the first national size standard in 1924. This was revised in 1926, 1928, 1939, and 1953, while still another revision is proposed for adoption in 1964.
What is nominal length?
In manufacturing, a nominal size or trade size is a size “in name only” used for identification. The nominal size may not match any dimension of the product, but within the domain of that product the nominal size may correspond to a large number of highly standardized dimensions and tolerances.
What is a nominal dimension in construction?
Nominal Dimensions Nominal measurements traditionally refer to the size of the board when it was first rough cut, before it was dried and planed (smoothed). This is the measurement of the green board before any shrinkage has occurred.How do you calculate nominal size?
The nominal thickness of hardwood lumber is based on the quarter scale, 4/4, 5/4, 6/4, 8/4, etc. The rough size can be found by dividing the numerator by the denominator. For example, 8/4 lumber is roughly 2” thick (8 divided by 4 equals 2). But once again, the quarter-scale is the nominal thickness.
What are the actual dimensions of a 2x12?Nominal SizeActual Size2 x 61 1/2 x 5 1/2 inches (38 x 140 mm)2 x 81 1/2 x 7 1/4 inches (38 x 184 mm)2 x 101 1/2 x 9 1/4 inches (38 x 235 mm)2 x 121 1/2 x 11 1/4 inches (38 x 286 mm)
Article first time published onWhat are the dimensions of a 2x4 piece of wood?
The true measurement of a 2×4 is actually about 1.5×3. 5. When the board is first rough sawn from the log, it is a true 2×4, but the drying process and planning of the board reduce it to the finished 1.5×3. 5 size.
What are the actual dimensions of a 6x6?
Nominal SizeActual Size2x121-1/2″ x 11-1/4″4×43-1/2″ x 3-1/2″4×63-1/2″ x 5-1/2″6×65-1/2″ x 5-1/2″
Why is it called 5 4 board?
The thickness of hardwood lumber is measured in quarters of an inch. … 5/4 (five-quarter) lumber is 1.25″ thick when rough sawn. When 5/4 lumber is planed, typically it is finished at 1.063″ thick. 6/4 (six-quarter) lumber is 1.5″ thick when rough sawn.
What is the difference between nominal and actual?
Nominal size is the size you see printed on the side of your air filter. It stems from the actual size, which is rounded up to the nearest whole inch.
What is #2 lumber?
2 Lumber. No. 2 lumber is the most common grade for framing. Lumber of this grade contains few defects, but knots are allowed of any quality as long as they are well spaced and do not exceed the size regulations.
Is basic size same as nominal size?
Basic size – The basic size is the size to which allowances and tolerances are added to get the limits of size. 4. Nominal size – The nominal size is a designation used for general identification. Typically this is a fraction when working in inches.
What is nominal size GD&T?
Nominal Size – The nominal size is the stated designation which is used for the purpose of general identification, examples: 1.400, . 050 . The term is used in a general conversation aboutthe materials or often to indicate the target as-manufactured size of a feature of size.
Why is a 2x4 not really 2x4?
DIMENSIONAL LUMBER: In the past, when a timber was called a 2×4 [or “two-by-four”], it actually measured 2 inches by 4 inches. … Because of this extra milling, a 2×4 no longer measures a full 2 inches by four inches. Instead, a 2×4 is really only 1 1/2″ by 3 1/2″. The same is true of pine.
What is the difference between timber and lumber?
In the US and Canada, timber is typically used to collectively refer to trees—or the wood of such trees—that have yet to be cut or processed, while lumber typically refers to wood that has been processed as a building material (boards and planks).
What type of wood are 2x4?
Fir, Hemlock and Pine Options One of the most commonly used two-by-fours for framing is made from softwood known as Douglas fir, with hemlock a close competitor. The two species share similar qualities of strength, appearance and durability and are often marketed together and sold as Hem-fir.
What does nominal mean for dimensions?
nominal dimension (nominal size) The sizes used to describe the approximate characteristics of the product rather than the exact dimensions.
What does nominal mean in drawings?
What does “nominal” mean when discussing a tolerance on a technical drawing? A nominal value represents the middle value of a range acceptable to fill a specification. The tolerance represents the range. The lowest and highest value acceptable for that middle number.
What is the difference between dimensional lumber and studs?
Light framing lumber is 2-inches to 4-inches thick and 4-inches wide. … Dimensional lumber and studs are 2-inches to 4-inches thick and 2-inches to 4-inches wide. Structural joists and planks are 2-inches to 4-inches thick and 6-inches wide. Beams and stringers are at least 5-inches wide and 2-inches thick.
How do you measure lumber and how is it calculated?
By Definition A single board foot of lumber measures 1 inch thick, 12 inches wide and 12 inches long. The formula for calculating board feet is first to multiply thickness by width by length — in inches. Then divide the total by 144 for the total board footage of a given board.
What are the actual dimensions of a 1x10?
1x Board Sizes The larger 1x boards (1×8, 1×10, etc.) lose 3/4 inch in width. That means a 1×10 is actually 3/4 inch in thickness by 9 1/4 inches.
How long is a 4x4 piece of lumber?
Rather, the retailers say, those are “nominal” designations accepted in government-approved industry standards, which also specify actual minimum dimensions — 1½ inches by 3½ inches for a 2×4, for example, and 3½ inches by 3½ inches for a 4×4.
What does BF mean in lumber?
1. Hardwood lumber is typically sold by the board foot, a unit of volume equivalent to a board that is one inch thick, one foot wide and one foot long, or 144 cubic inches.
Can I use 2x6 for deck boards?
Wood decking is commonly available in 2×6 and 5/4 x 6 profiles. 5/4 x 6 is produced specifically for decking and is milled with a radius edge or bull nose. 2×6 is thicker and is stronger, but is also more expensive. Spacing between deck boards provide a few critical functions.
What thickness is plywood?
The standard thicknesses for plywood are 1 ¼, 1 1/8, ¾, 5/8, ½, 3/8, ¼, and 1/8 inches. The corresponding actual thicknesses are 1 ¼, 1 1/8, 23/32, 19/32, 15/32, 11/32, 1/4, and ⅛, respectively.
What is nominal education length?
Nominal duration of program is the expected amount of time needed to complete any given program.