Free tool · Estimating & costing
Board Foot Calculator
Enter thickness, width, length, and an optional price to get total board feet and lumber cost in seconds. Fractions and quarter sizes (4/4, 5/4, 8/4) welcome.
Board feet are figured on nominal (rough) thickness, the size lumber is sold and billed at. A surfaced 13/16 inch board is still 4/4. Thickness accepts quarter sizes (4/4, 5/4, 8/4) or decimals and fractions.
Board Foot Calculator, explained
What is a board foot, and how do you calculate it?
A board foot is the standard unit hardwood lumber is priced and sold in. One board foot equals 144 cubic inches: a piece 1 inch thick, 12 inches wide, and 12 inches long. To calculate board feet, multiply thickness in inches by width in inches by length in inches, then divide by 144. If your length is in feet, multiply thickness by width by length in feet and divide by 12 instead.
Rough hardwood is graded in quarter-inch thicknesses, so the trade writes thickness as quarters: 4/4 is 1 inch, 5/4 is 1.25 inches, 6/4 is 1.5 inches, and 8/4 is 2 inches. Board feet are figured on the rough thickness before surfacing, which is why a planed 13/16 inch board is still sold as 4/4. Enter your numbers above and this calculator returns total board feet, plus the cost when you add a price per board foot.
How it works
How the Board Foot Calculator works.
Board feet = (Thickness in inches × Width in inches × Length in inches) ÷ 144 × Quantity - Enter the board thickness in inches. Use the quick chips for standard quarter sizes (4/4, 5/4, 6/4, 8/4) or type any value, including fractions like 1 1/4.
- Enter the width in inches. Fractions are fine, for example 5 1/2.
- Enter the length and choose inches or feet with the toggle.
- Set the quantity if you are pricing more than one identical board.
- Add a price per board foot to get the total lumber cost alongside the board footage.
Example: ten 8/4 walnut boards, each 6 inches wide and 8 feet long, at $9.50 per board foot. That is (2 × 6 × 96) ÷ 144 = 8 board feet per board, 80 board feet total, for $760.
Board Foot Calculator FAQ
Board Foot Calculatorquestions.
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How do you calculate board feet?
Multiply thickness in inches by width in inches by length in inches, then divide by 144. For example a board 2 inches thick, 6 inches wide, and 96 inches long is (2 × 6 × 96) ÷ 144 = 8 board feet. If your length is measured in feet, divide by 12 instead of 144.
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What does 4/4, 5/4, and 8/4 mean?
Hardwood is graded in quarter-inch thicknesses, so 4/4 means four quarters, or 1 inch. 5/4 is 1.25 inches, 6/4 is 1.5 inches, and 8/4 is 2 inches. Board feet are always figured on this rough nominal thickness, not the thinner surfaced dimension.
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Is a board foot the same as a linear foot?
No. A linear foot measures length only. A board foot measures volume: thickness times width times length. Two boards can be the same linear footage but very different board footage if their thickness or width differs. Use board feet for hardwood pricing and linear feet for trim and molding.
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Should I use rough or finished thickness?
Use the rough nominal thickness for board footage, because that is what the mill charges for. A 4/4 board planed to 13/16 inch is still sold and calculated as 1 inch thick.
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Is this board foot calculator free?
Yes. Every tool from Fast Kitchen Design is free to use with no sign-up. We build them for the cabinet trade because design is what we charge for, at a flat $100 per design.
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