Board Feet Calculator

Calculate the total board feet volume of hardwood lumber for dimensional boards, framing, and wood manufacturing projects.

Results are estimates. Check physical dimensions before purchasing.

Rough thickness before planing

Rough width of the boards

Length of individual board pieces

Number of boards of this size

How to calculate board feet

A board foot is a unit of volume measurement commonly used in the lumber trade. One board foot represents a volume of 144 cubic inches. This is the equivalent of a board that is 1 inch thick, 12 inches wide, and 1 foot (12 inches) long.

The Board Feet Formula

Board Feet (BF) = (Thickness (inches) × Width (inches) × Length (feet)) / 12
Total Board Feet = Board Feet (BF) × Quantity

Dimensional Lumber vs. Rough Hardwoods

When buying softwood construction lumber (like 2x4s or 2x6s), boards are sold by their nominal sizing and linear feet. However, high-quality hardwoods (like oak, maple, walnut, and cherry) are typically sold by volume in board feet. Hardwoods are often priced using a quarter-thickness classification system:

  • 4/4 (four-quarter) lumber: Measures roughly 1 inch thick before planing.
  • 5/4 (five-quarter) lumber: Measures roughly 1-1/4 inches thick.
  • 6/4 (six-quarter) lumber: Measures roughly 1-1/2 inches thick.
  • 8/4 (eight-quarter) lumber: Measures roughly 2 inches thick.

Practical calculation tip

Remember that when calculating board feet, you should use the **nominal size** (the rough dimension before planing and surfacing) rather than the actual finished dimensions. For example, a dry surfaced 2x4 board actually measures 1-1/2 inches by 3-1/2 inches, but for pricing volume, it is calculated as a nominal 2 inches by 4 inches.

Frequently Asked Questions