Board Foot Calculator (Lumber & Hardwood)
Calculate board feet (FBM) for hardwood and dimensional lumber with cost estimates.
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How to Use the Board Foot Calculator
- 1Enter the lumber thickness in inches (e.g. 4/4 = 1 inch, 8/4 = 2 inches).
- 2Enter the width in inches.
- 3Enter the length in feet or inches.
- 4Optionally enter piece quantity and price per board foot to view total lumber cost.
Formula & How It Works
Board Foot Formula
One board foot equals the volume of a 1-inch thick piece of wood that is 12 inches wide and 12 inches (1 foot) long (144 cubic inches).
Worked Examples
Hardwood Walnut Board
Input: Thickness: 2 in, Width: 8 in, Length: 8 ft, Qty: 3
Explanation: (2 × 8 × 8) / 12 = 10.67 BF per board. 10.67 × 3 = 32 BF.
Quarter Sawn White Oak (4/4 stock)
Input: 1 in × 6 in × 10 ft, Qty: 4 at $8.50/BF
Explanation: (1 × 6 × 10) / 12 = 5 BF per board. 5 × 4 = 20 BF. 20 × $8.50 = $170.
Frequently Asked Questions
What does 4/4, 6/4, or 8/4 mean in hardwood?▼
Hardwood thickness is measured in quarters of an inch: 4/4 is 1 inch thick, 6/4 is 1.5 inches thick, and 8/4 is 2 inches thick.
Is board foot measured before or after planing?▼
Board feet for rough hardwood are measured based on nominal rough-sawn dimensions before final surfacing (S2S/S4S).
Can length be entered in inches?▼
Yes, if length is entered in inches, the formula divides by 144: (T × W × L) / 144.
How do I account for woodworking scrap?▼
Woodworkers generally add 15% to 20% extra board footage to account for defects, milling, and kerf loss.
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