Board Foot Calculator
The lumber math staple. Convert dimensioned lumber (thickness × width × length × quantity) to board feet, the standard volume unit for hardwood, cedar, and tropical lumber pricing. 13 species — pressure-treated SYP, cedar Western Red, redwood, Douglas fir, hemlock, white oak, mahogany, IPE, cumaru, tigerwood, garapa, massaranduba + more. Multi-row mode rolls up a full deck BoM (joists + decking + posts) with mixed species. Weight (lbs) + cost range + heavy-load delivery advisory.
Inputs
Advisories
PT lumber in order — fastener advisory
IRC R317 + ICC-ES ESRModern PT chemistry (ACQ, MCA, CA-C, CuN) is corrosive to coated steel. Use hot-dip galvanized G185 or stainless 305 fasteners for all PT-to-PT connections. Standard coated screws will fail within 3-7 years.
Per-row breakdown
BF = (thickness_in × width_in × length_ft × quantity) ÷ 12Always use nominal dimensions — a "2×10" is 2″ × 10″ nominal, not 1.5″ × 9.25″ actual.Need a full deck cost?
The Deck Cost Calculator gives you a complete project budget — materials, labor, permits, contingency — across 5 finish tiers.
Board feet uses nominal dimensions per ANSI/NIST PS 20. Cost ranges are 2026-Q1 national-median retail; expect ±20% variance from your local lumber yard. Weight uses kiln-dried density values from ASTM D2555. DeckMath is not affiliated with any lumber supplier.
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How to use
How to use the board-foot calculator in 5 steps.
- 1
Pick single-row or multi-row mode
Single-row is the quickest answer for one lumber size ("how many BF in 12 pieces of 2×10 × 12 ft?"). Multi-row is the deck-BoM mode — up to 8 rows, each with its own thickness × width × length × qty + optional row-specific species + label (Joists / Decking / Beam / Posts etc).
- 2
Choose a default species
13 species across softwood, cedar, hardwood, and tropical. Default species applies to every row unless you override a specific row. Density (lbs/cf) drives weight; retail $/bf range drives cost. Heavy tropicals (IPE, Massaranduba) at 64-69 lbs/cf weigh 2-3× softwoods.
- 3
Enter dimensions per row
Thickness (in) × Width (in) × Length (ft) × Quantity (pieces). Use nominal dimensions (a "2×10" is nominally 2″ × 10″ — the calculator uses these for BF math, not the actual 1.5″ × 9.25″ S2S dimensions). Common drop-downs cover 1, 1.25, 1.5, 2, 3, 4, 6 thickness and 2-12 width.
- 4
Toggle weight + cost
Weight uses species density × volume; cost uses the species' national-median $/bf range × your state's regional multiplier. Turn off either if you just want pure BF math.
- 5
Read your BoM
Per-row breakdown shows BF + LF + weight + cost range. Totals roll up across all rows. Heavy-load flag (≥2000 lbs) advises delivery vs trailer haul. Save link, export PDF, embed.
How we calculate
How DeckMath calculates this — IRC 2021 sources.
The Board Foot Calculator converts dimensioned lumber to board feet — the standard volume unit for hardwood, cedar, and tropical lumber pricing. Enter thickness, width, length, and quantity; pick a species, and the calculator returns total board feet, total linear feet, lumber weight (lbs), and cost across a 2026-Q1 retail price range. Multi-row mode lets you build a full deck BoM in one calc — joists at 2×10 × 12 ft × 12 pcs + decking at 5/4×6 × 16 ft × 20 pcs + posts at 6×6 × 10 ft × 4 pcs — and roll up board feet + weight + cost across mixed species. 13 species covered: pressure-treated SYP, cedar (Western Red), redwood, Douglas fir, hemlock, white oak, mahogany, IPE, cumaru, tigerwood, garapa, massaranduba, untreated SYP.
IRC references
- ANSI/NIST PS 20 — American Softwood Lumber Standard
- AWC NDS — National Design Specification for Wood Construction (board foot used for material orders + structural calcs)
- AWC DCA-6 — Prescriptive Residential Wood Deck Construction Guide (PT lumber sizing)
- ASTM D2555 — Establishing Clear Wood Strength Values (density references)
Verify against the published source: 2021 International Residential Code (ICC).
Density values from ASTM D2555 kiln-dried hardwood/softwood reference tables. Retail $/bf ranges reflect 2026-Q1 national-median pricing at common grades (PT #2, Cedar Select Tight Knot, Hardwood FAS). Regional multiplier uses RSMeans 2026-Q1 residential index. Always use nominal lumber dimensions per ANSI/NIST PS 20.
The standard board foot is 144 cubic inches of nominal wood (1″ × 12″ × 12″ = 144 in³). The formula expresses this as the wood volume in cubic feet × 12. Always use NOMINAL dimensions (the "2×10" not the actual 1.5″ × 9.25″).
Total linear feet across all pieces of a given dimension. Useful for ordering — lumber yards quote per-LF for many softwoods and decking species. Different from BF: a 2×10 × 12 ft is 12 LF but 20 BF.
Volume in cubic feet = (thickness_in × width_in × length_ft × qty) ÷ 144. Then weight = volume × species density. PT SYP 36 lbs/cf, Cedar 23, IPE 69, etc. Used for delivery + trailer planning.
$/bf is the national-median retail range for that species at the typical grade (PT #2, Cedar Select Tight Knot, Hardwood FAS). Region multiplier: Northeast 1.20×, Midwest 1.00×, South 0.92×, West 1.15×, Mountain 0.98×.
Useful when converting to other units. 1 BF = 1/12 cubic foot. 100 BF of any species ≈ 8.33 cubic feet of wood.
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People also ask
Board-foot questions, answered.
A board foot is a unit of lumber volume equal to 144 cubic inches — typically a 1-inch-thick board that's 12 inches wide and 12 inches long. The formula is BF = (thickness_in × width_in × length_ft × quantity) ÷ 12. Used industry-wide for hardwood, cedar, and tropical lumber pricing. A single 2×10 × 12 ft piece equals 20 board feet ((2 × 10 × 12 × 1) ÷ 12).
Linear feet (LF) measures just the length of the board — a 2×10 × 12 ft is 12 LF regardless of cross-section. Board feet (BF) measures the volume — same 2×10 × 12 ft is 20 BF. Pressure-treated framing lumber is usually priced per linear foot at the box store ($X.XX per 8-ft 2×10); hardwood and tropical lumber is priced per board foot from specialty suppliers ($Y.YY per BF). The calculator gives you both numbers.
Always nominal. A "2×10" is sold and priced as a 2-inch by 10-inch board even though the surfaced (S2S) actual dimension is 1.5″ × 9.25″. Board foot math always uses nominal dimensions — that's the industry standard. If you used actual dimensions you'd undercount your BF by roughly 28%.
Depends heavily on species. A 16×20 ft pressure-treated deck (joists 2×10 × 12 ft × 14 pcs + decking 5/4×6 × 16 ft × 28 pcs + posts 6×6 × 10 ft × 6 pcs ≈ 540 BF) weighs about 1620 lbs in PT (36 lbs/cf × 45 cf). The same deck in IPE weighs 3100 lbs (69 lbs/cf). For IPE: order delivery, don't trailer-haul. For PT: a 1500-lb load is manageable in a single F-150 bed.
Three reasons: (1) growing region + import duties (tropicals like IPE ship from Brazil with export tariffs); (2) density — heavier wood costs more to harvest, mill, and ship; (3) durability — naturally rot-resistant species (cedar, redwood, tropicals) command a premium because they outlast PT in outdoor use. PT SYP at $1.20-2.40/bf is the budget option; IPE at $8.50-14/bf is 5-7× the price but lasts 3× longer with proper maintenance.
Pressure-treated SYP at $1.20-2.40/bf is the cheapest by a wide margin. Untreated SYP is cheaper still but can't be used outdoors. PT lasts 15-25 years in service depending on grade + treatment + climate. If you want a non-PT look, Cedar Western Red at $3.50-5.50/bf is the next-cheapest naturally rot-resistant option.
The price ranges are 2026-Q1 retail national-median for typical grades (PT #2, Cedar Select Tight Knot, Hardwood FAS). Expect ±20% variance from your actual lumber yard quote. Specialty hardwood suppliers (J. Gibson McIlvain, IPE Woods USA) often beat box-store retail by 15-25% on tropical species when buying in volume (200+ BF orders).
Yes — board foot math is universal for any dimensional lumber. Use it for framing (2×4 wall studs, 2×10 floor joists), interior trim, furniture-grade hardwood orders, etc. The species catalog focuses on decking + framing species, but you can use "untreated SYP" or "white oak" or "mahogany" entries for any project where those species apply.
Regional lumber pricing varies up to 30% across the US. The calculator applies a region multiplier: Northeast 1.20×, West Coast 1.15×, Mountain 0.98×, Midwest 1.00× (baseline), South 0.92×. So a $1000 PT order in Pennsylvania (NE) costs ~$833 in Texas (South). The state input doesn't change board feet or weight — only the cost output.
The action bar generates a printable PDF with the per-row breakdown + totals + species notes. CSV export gives you a spreadsheet-ready file. Copy Link preserves all your inputs in the URL so a lumber supplier can open the same calculation. Embed code lets you put the calculator on a contractor blog or quote-tool page.
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