Board Foot Calculator

How board feet are calculated

A board foot is a volume of lumber equal to a piece 1 inch thick, 12 inches wide and 12 inches long — that is 144 cubic inches. The formula with every dimension in inches is:

• Board feet per piece = (thickness × width × length) ÷ 144
• Total board feet = board feet per piece × quantity
• Total cost = total board feet × price per board foot

If you measure length in feet instead of inches, multiply that figure by 12 first, or use the equivalent formula (thickness × width × length-in-feet) ÷ 12.

Worked example

Say you need ten boards, each 2 inches thick, 8 inches wide and 96 inches (8 ft) long, at $4.50 per board foot:

• Board feet per piece = (2 × 8 × 96) ÷ 144 = 10.67 bf
• Total board feet = 10.67 × 10 = 106.7 bf
• Total cost = 106.7 × 4.50 = $480.00

Common board sizes

Pitfalls to avoid

• Mixing units. Every dimension must be in inches for the ÷ 144 formula. A length entered in feet inflates the result twelve-fold.
• Using the planed size. Hardwood is graded and sold on its rough thickness (a 4/4 board is 1 inch rough even though it finishes thinner). Price on the rough size or you will under-order.
• Forgetting waste. Board feet measure volume, not usable yield. Add 15–30% for cuts, knots and grain matching, especially for furniture-grade stock.
• Confusing board feet with linear feet. Two boards of the same length can have very different board feet if their thickness or width differs.