Board Foot vs. Square Foot

Defining the Units

In the world of construction and woodworking, mixing up area and volume can lead to expensive errors at the lumber yard. Before you place your next order, you must understand how these two measurements interact.

Square Foot (SF): This is an area measurement. It tells you how much surface the wood covers. For example, a deck or a floor is typically measured in square feet.

Board Foot (BF): This is a volume measurement. It tells you how much total wood fiber is in the piece. It is used exclusively for pricing hardwood lumber in the USA.

The Critical Distinction: Thickness

The "missing link" between square feet and board feet is **thickness**. If you have a board that is 12" wide and 12" long, you have 1 Square Foot of surface area. However, the Board Foot volume will change based on how thick that board is:

• 1" Thick: 1 Square Foot = 1 Board Foot.
• 2" Thick: 1 Square Foot = 2 Board Feet.
• 1/2" Thick: 1 Square Foot = 0.5 Board Feet.

How to Convert SF to BF

To find the board foot volume of a surface area, use this simple formula:

If you have 100 square feet of oak flooring that is 3/4" thick, you will actually be buying 75 Board Feet of material.

When to Use Each Unit

Standardizing your project plan according to industry units will save time during the ordering process:

• Use Square Feet for: Sheet goods (Plywood, MDF), flooring coverage, wall paneling, and decking surfaces.
• Use Board Feet for: Rough lumber, s2s hardwoods, timber framing, and mill pricing.

Comparison Summary Table