What is a Board Foot?

In the United States and Canadian timber industries, a board foot (BF or FBM) is the standard unit of measurement used to quantify the volume of lumber.

The Exact Definition

One board foot is defined as a piece of rough, un-surfaced wood that is:

• 1 foot long
• 1 foot (12 inches) wide
• 1 inch thick

Mathematically, this equals exactly 144 cubic inches of solid wood material.

Why Does the Industry Use It?

While standard construction materials like 2x4s are milled to uniform sizes and sold by length, premium hardwoods are milled into random widths and lengths to maximize the yield of the tree. Because every board is a unique size, selling them by length is impossible. Instead, sawmills price the wood based on its total three-dimensional volume, allowing for fair pricing regardless of the board's shape.

To easily determine the total FBM (Foot Board Measure) of any random-width hardwood slab, use our free Board Feet Calculator.