Linear vs. Lineal, Uses, vs. Board Feet

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Linear refers to a straight line or lines vs. lineal, which means descended in a direct line from an ancestor. Both terms have use in manufacturing and distribution. In this article, you will learn the definition of linear vs. lineal, uses and board feet.

What is Linear?

self-retracting style tape measure that's designed for carpentry
Courtesy: U-Pack

Identifying a linear foot is right in the name. Technically, a linear foot is a measurement that is 12 inches long or one foot. It is measured in a straight line, which is why it’s called linear. In short, a linear foot is simply twelve inches that are in a straight line. 

Many construction materials sell in the linear foot. It includes boards and other oblong materials that depend on length rather than width. 

What is Lineal?

An example of direct line of descent - from the grandparents down to grandchildren and so on
Courtesy: Medium

Lineal, in legal usage, is a blood relative in the direct line of descent. The children, grandchildren, great-grandchildren, etc. of a person. In a legal procedure sense, lineal descent refers to acquiring an estate by inheritance by a parent from a grandparent and by a child from a parent. In engineering, the term lineal denotes the length of something with an implied dimension, usually width.

Use of Lineal Feet vs. Linear Feet

When measuring length, engineers use the term linear much more frequently vs. lineal. In construction, manufacturing, and engineering, the terms lineal vs linear often interchange without any loss of meaning. However, engineers should understand the difference.

Lineal describes a quantity of material with an implied width dimension, and linear describes a distance regardless of width. Lineal units are used by OEM manufacturers, distributors, and engineers. Anyone taking a length measurement expresses it as a linear team. However, the distinction has begun to erode recently.

Using linear feet as a measurement
Courtesy: Inch Calculator

Consider the following example: “If a single metal panel requires repair and the building’s sidewall is 12 linear feet to the eave, you’ll need to order 12 lineal feet of metal.” 

The stated material width permanently establishes a conversion factor for converting lineal feet to square feet, yet this concept does not apply to measures that utilize the term linear. However, online converters for the retail market distribute widely. Manufacturers, distributors, and engineers generally do not market directly to consumers. Therefore no readily available reference describes the specific meaning of lineal used in industry. 

Linear Feet vs. Board Feet

Measuring a lumber wood - identifying its length, width and thickness
Courtesy: PNGitem

In the United States and Canada, board feet provide a unit of measurement for the volume of lumber. It equals a one-foot (305 mm) length of a board, one foot wide, and one inch (25.4 mm) thick. In lumberyards, board feet determine the price of wood. This type of measurement becomes necessary because boards can’t sell just based on length, a two-dimensional concept. Boards price on volume, hence the board feet notation.

Linear foot measurements occur when a simple measurement is required. The object’s thickness or “dimension” is irrelevant because the designed characteristic is a linear measurement. Occasionally, hardware sells by linear foot. However, it’s generally reserved for door trim or something similar. A simple tape measure provides the length of the subject board or trims via linear feet.

When purchasing wood from a lumberyard, measurements typically register in board feet. It’s nearly always sold this way because the volume of the wood provides an obvious factor in the total cost of the timber.

Board feet calculations are easy to perform. To determine the board feet from a piece of lumber simply use the standard formula:

Board ft = [thickness (in) * width (in) * length (ft)] ÷ 12 in.

The resultant units report in 1,000 board feet (MBF).

For example, to determine the board feet for an 8′ long board that’s 2 inches thick and 4 inches wide, the following calculation would occur:

Board ft = [thickness (in) * width (in) * length (ft)] ÷ 12 in

Board ft = [8*2*4]/12 = 5.333 MBF

In summary, the use of linear feet vs. board feet depends on the required need. Knowing the industrial purposes each serve helps engineers understand the practical benefit of both terms.