Board Foot Calculator
Free board foot calculator: thickness × width × length ÷ 12. Board feet per piece, totals, and cost with 2026 hardwood prices from $5.50/BF.
Board feet are how US hardwood dealers price lumber: one board foot equals 144 cubic inches of rough-sawn wood — a piece 12 inches long, 12 inches wide, and 1 inch thick. The calculator above multiplies pieces × thickness (inches) × width (inches) × length, divides by 12 when length is in feet, and returns board feet per piece, the running total, and the cost at whatever price per board foot you enter. It accepts fractional thickness and has one-tap presets for the hardwood quarters system — 4/4 (1 inch), 5/4, 6/4, 8/4, and 12/4 — so you can price a lumber run the way the yard actually tags it. At 2026 retail prices running from about $5.50 per board foot for red oak to $18 for walnut, a mis-measured stack gets expensive fast; this page covers the formula, the quarters system, nominal-versus-actual confusion, and how much waste to add.
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, then divide by 12 — a 4/4 board (1 inch thick) that’s 6 inches wide and 8 feet long is 1 × 6 × 8 ÷ 12 = 4 board feet. If you measure length in inches, divide by 144 instead. The calculator at the top of this page runs the formula per piece, totals a full lumber order, and multiplies by your price per board foot.
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Board Foot Calculator
Key Information
| Parameter | Details |
|---|---|
| Board foot formula | thickness (in) × width (in) × length (ft) ÷ 12 |
| One board foot | 12 in × 12 in × 1 in = 144 cubic inches |
| 4/4 surfaced thickness | 13/16 in (NHLA S2S standard) |
| 2026 walnut retail | $10–18 per board foot |
Frequently Asked Questions
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, then divide by 12 — a 4/4 board (1 inch thick) that’s 6 inches wide and 8 feet long is 1 × 6 × 8 ÷ 12 = 4 board feet. If you measure length in inches, divide by 144 instead. The calculator at the top of this page runs the formula per piece, totals a full lumber order, and multiplies by your price per board foot.
How many board feet are in an 8-foot 2×4?
Nominally 5.33 board feet (2 × 4 × 8 ÷ 12), but only 3.5 by actual dimensions, because a surfaced 2×4 measures 1-1/2 by 3-1/2 inches. In practice the question rarely matters: softwood construction lumber is sold by the piece or linear foot, not by the board foot. Board-foot pricing is a hardwood convention based on rough-sawn dimensions.
What does 4/4 mean in lumber?
4/4 (“four-quarter”) means the board was sawn 1 inch thick — hardwood thickness is quoted in quarter inches of rough thickness, so 5/4 is 1-1/4 inches, 8/4 is 2 inches, and 12/4 is 3 inches. Surfacing removes material: 4/4 planed on two sides measures 13/16 inch under NHLA standards. You still pay board feet on the full rough thickness, which the calculator’s quarter presets load automatically.
Are these calculators free to use?
Yes, all calculators on CalcCorp are completely free — no registration, no login, no hidden charges. Results are calculated instantly in your browser and we do not store any of your data.
How accurate are these calculations?
Our calculators use standard financial formulas updated with the latest tax rates, interest rates, and government policies for 2026. Results are accurate for planning purposes but should be verified with a professional for final decisions.
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Last updated: March 2026