Lumber calculations can be confusing, even for veteran woodworkers.  At Rockler Woodworking and Hardware, we make every effort to simplify the process. Below, we'll go over some of the most common methods for pricing lumber, explain Rockler's method for calculating the cost of lumber, and introduce our time and calculation saving Lumber/Veneer Configurator.

Common Methods for Pricing Lumber
Lumber is usually sold in one of two ways: by the lineal inch, or by some method based on the square foot dimensions of the lumber being sold.  Of the two, the "lineal inch" method of pricing lumber is the simplest and most familiar. Lumber sold by the lineal inch is cut to a specific width before it is offered for sale. The price is determined by the length of the material being purchased. A 12'' long hardwood board priced at $.10/ln. in. costs $1.20.

"Random-width lumber" is lumber that's not cut to a specific width before it is sold. As the name implies, the width of boards sold as random-width lumber varies.  Woodworkers who buy random-width lumber cut the lumber to width themselves, and understand that some amount of waste will be generated in the process.

A pricing system for random-width lumber has to take the varying widths of the boards being sold into account. The most common method of pricing random-width lumber is by the "board foot." Board feet are calculated by multiplying the surface area of the lumber (measured in square feet) by the thickness of the lumber (measured in inches).

Examples:

A board that's 1'' thick, 12'' wide and 24'' long is:
(1 foot wide) x (2 feet long) x (1 inch thick) = 2 board feet of lumber.

A board that's 2'' thick, 12'' wide and 24'' long is:
(1 foot wide) x (2 feet long) x (2 inches thick) = 4 board feet of lumber.

How Rockler Prices Lumber
Rockler Woodworking and Hardware offers lumber in certain species cut to specific widths and sold by the lineal inch. Rockler also offers certain species of random-width lumber priced by the surface area of the lumber.

Rockler's method of pricing random-width lumber differs slightly from the "board foot" method described above.  The main difference is simply that the "thickness factor" is taken out of the equation. In other words, Rockler calculates the best price possible for each thickness of a given species of random-width lumber and prices the lumber based strictly on it's square-foot dimensions. 

In addition, Rockler offers lumber in units of tenths of a square foot (TSF). The purpose of offering lumber in 1/10 square foot units (as opposed to the usual 1 square foot or 1/2 square foot minimum) is to allow customers to order lumber in quantities that are as near as possible to their exact needs.  The lumber prices you'll find on the Rockler website in individual random-width lumber offers are the cost of 1/10 square foot (TSF) of lumber. 

Ordering Lumber from Rockler
On the Rockler website, lumber offers are divided into two categories: lumber sold by the lineal inch, and lumber sold in units of 1/10 square foot. In each of the lumber offers on the Rockler website, you'll find an order form that lists the prices of the various dimensions of lumber offered.

To order lumber from the Rockler website, simply follow the instructions in the lumber offer.  Each lumber offer is linked to the Rockler Lumber/Veneer Configurator, which calculates the cost of the lumber you order based on the dimensions you supply.  Please remember that requests for specific widths of random-width lumber are subject to availability.  

Calculating the Cost Yourself
Even though our lumber configurator does all of the calculations necessary for lumber orders, we know that some woodworkers prefer to do the math themselves before they place an order.  Here's how to calculate the cost of random-width lumber offered on the Rockler website:

Determine the Number of Square Feet of Lumber Needed.
The number of square feet of a piece of lumber is calculated by multiplying the length of the piece (in inches) by the width of the piece (in inches) and dividing the product by 144.

Example: A board that's 4'' wide and 60'' long is:

(4 x 60) / 144 = 1.67 square feet.

Determine the Number of Tenths of a Square Foot (TSF) of Lumber Needed.
To calculate the cost of the lumber you order, you'll need to convert square feet into tenths of a square foot (TSF). This is just a matter of multiplying the number of square feet by 10 and rounding the number up to the nearest tenth of a square foot.

Example: The number of tenths of a square foot (TSF) in 1.67 square feet is:

1.67 x 10 = 16.7 TSF;

Rounded up to the nearest tenth of a square foot, thats:

17 TSF

Find the Cost of the Lumber
To find the total cost of the lumber, multiply the total number of tenths of a square foot (TSF) of lumber you plan to order by the price listed in the lumber offer.

Example: The cost of 17 tenths of a square foot (TSF) of lumber priced at $.35/TSF is:

17 x .35 = $5.95