What is a Board Foot?

What is a Board Foot?

A board foot is a wood measurement for a piece of lumber 12" wide by 1' long by 1" thick for estimating purposes. Board foot, or board feet, is commonly abbreviated as FBM, BDFT, or BF. Learn how to figure board feet in your next stack of lumber below.

How to Calculate Board Feet

Sawmillers and most suppliers use board feet as a unit of wood measurement. It's important for you to know and understand how to calculate board feet and board feet pricing for your sawmill business.

The basic calculation for board feet is:

Thickness X Width X Length / 12 = BDFT

1" T X 12" W X 1' L / 12 = 1 BDFT

A 2 X 4 - 10' has 6.667 board feet:

2 X 4 X 10 / 12 = 6.667 BDFT

A 2 X 10 -16' has 26.67 board feet:

2 X 10 X 16 / 12 = 26.667 BDFT

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

PCS X T X W X L / 12 = BDFT

To calculate the board footage in an 84 piece unit of 2 X * - 12:

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

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 BDFT

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

1 X 6 X 14 / 12 = 7 BDFT

Another way to quickly calculate board feet is to memorize the board feet in each lineal 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 BDFT

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

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 because there are 144 square inches in a square per 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 BDFT

Now you know how to calculate board foot in a piece of lumber. Learn how to charge per board foot in the How to Charge for Sawing Services article.