## Board Foot Calculations

A board foot is a piece of lumber 12″ wide by 1′ long by 1″ thick for estimating purposes. Some customers and most suppliers still use board feet as a unit of measure. It’s important for you to know and understand how to calculate board feet and board feet pricing.

The basic calculation for board feet (BFT) is:

Thickness X Width X Length / 12 = BFT
1″ T X 12″ W X 1’L / 12 = 1 BFT

A 2 X 4 – 10′ has 6.667 board feet:

2 X 4 X 10 / 12 = 6.667

A 2 X 10 -16′ has 26.67 board feet:

2 X 10 X 16 / 12 = 26.667

To calculate the board footage for a number of pieces at one time:

PCS X T X W X L / 12 = BFT

To calculate the board footage in a 84 piece unit of 2 X * – 12:

84 X 2 X 8 X 12 / 12 = 1,344 BFT

It’s important to remember that 5/4 stack-like deck plank, is considered thicker than 1″ stock. This means when calculating board footage for 5.4″ stock you must use 1.25 as the thickness instead of 1. For example, to calculate the board footage of a 5/4 X 6-14′ piece of material:

1.25 X 6 X 14 / 12 = 8.75 BFT

Compare this to the board foot calculation for a standard 14′ board:

1 X 6 X 14 / 12 = 7 BFT

Another way to quickly calculate board feet is to memorize the board feet in each foot of standard dimensional material. For example, there is .667 board feet in 1 lineal foot of 2 X 4. To calculate the board footage by the length:

.667 X 10 = 6.67 BFT

The table below lists the board feet in a 1′ piece of lumber for each dimension:

 1×4=.334 2×4=.667 1×6=.5 2×6=1 1×8=.667 2×8=1.334 1×10=.834 2×10=1.667 1×12=1.0 2×12=2.0 5/4×4=.416 5/4×6=.625

When calculating the board feet in a random width product, such as oak boards, you use the actual width in inches, not the nominal width. Since you use the actual width in inches in the calculation you also enter the length in inches as well, then divide by 144, instead of 12 (there are 144 square inches in a square/board foot).

Let’s say you have a piece of random width oak with an actual size of 7/8″ thick by 7 3/4″ wide by 63″ long. The board foot calculation for this piece would be:

1 X 7.75 X 63 / 144 = 3.39 BFT