Wood Technology & Processes

Math Activities :

Math Activity 10

Figuring Board Feet

Woodworkers often use a type of measurement that indicates the total volume of wood in a board. This measurement is called a board foot (bf or b.f.). One board foot is equivalent to 144 cubic inches of wood. This can also be thought of as a piece of wood 1" thick, 12" wide, and 12" long. Board footage is often used in estimating the cost of materials in large quantities. However, it is also possible to compare the cost of individual boards, even if they have different dimensions. To determine board footage, the length, width, and thickness of a board must be known.

Two formulas can be used to figure board feet. Using all inches, the formula is:

T × W × L(all in inches) ÷ 144 = bf

Using inches and feet, the formula is:

T (in inches) × W (in inches) × L (in feet) × 12 = bf

Terms, Symbols, & Abbreviations
board foot-a measure of volume equal to a piece of lumber 1" × 12" × 12" in size

Practice Exercise

Determine the board footage of a board measuring 1" × 6" × 8' using Formula 1.

Step 1 Convert 8 feet to inches.
 
8 x 12 = 96
  
Step 2Multiply the dimensions in inches.
 
1 × 6 × 96 = 576
  
Step 3Divide the total by 144.
 
576 ÷ 144 = 4 bf

Hint: Stock less than 1" thick is figured as 1". Stock more than 1" thick is figured by actual measurement.

Problem Exercises

1.

Find the board footage of a board 2" × 6" × 8'.
A)12 bf
B)8 bf
C)4 bf
D)96 bf
2.

Find the board footage of a post that is 6" square and 14' long.
A)504 bf
B)84 bf
C)42 bf
D)7 bf
3.

A load of hardwood lumber has been delivered to your shop. It contains fifty 1 × 6 boards 12' long and twenty 2 × 6 boards 8' long. What is the total board footage in this load?
A)460 bf
B)300 bf
C)160 bf
D)110 bf
4.

A lumber supplier will sell kiln-dried cherry for $6.50 per board foot. You need ten boards that are 8/4" × 6" × 8' long. How much will this cost?
A)$260
B)$960
C)$520
D)$120
5.

What is the board footage of an oak plank that is 4" × 6" × 96" long?
A)192 bf
B)16 bf
C)18 bf
D)20 bf
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