Board Feet Calculator
Use this board feet calculator to estimate lumber volume for woodworking and construction projects using standard US measurements.
Enter nominal dimensions (listed size), not actual milled dimensions · 1 BF = 1″ × 12″ × 12″ = 144 cu in · Add 10–15% for waste and defects · Hardwood is typically priced per BF at lumber yards
How to Calculate Board Feet
A board foot (BF) is a unit of lumber volume equal to a piece of wood 1 inch thick × 12 inches wide × 12 inches long (144 cubic inches). It’s the standard pricing unit for hardwood lumber at sawmills, lumber yards, and woodworking suppliers.
The Board Feet Formula
Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12
This formula is the industry-standard method used by every hardwood lumber dealer in the US. The division by 12 converts the result from the product of two inch dimensions and one foot dimension into board feet. Always use nominal dimensions (the stated size, e.g. 1×6), not the actual milled dimensions (e.g. 0.75″ × 5.5″).
Quick Examples
- A 1″ × 6″ × 8 ft board: (1 × 6 × 8) ÷ 12 = 4 BF
- A 2″ × 4″ × 8 ft board: (2 × 4 × 8) ÷ 12 = 5.33 BF
- A 4″ × 4″ × 12 ft post: (4 × 4 × 12) ÷ 12 = 16 BF
Board feet measure volume, which is why hardwood dealers use them — a wider or thicker board contains more lumber for the same length. A 1×4 board is narrower than a 1×8; charging the same per linear foot would undercharge for the 1×8. Board feet pricing ensures the buyer pays proportionally to the actual wood content in the board, regardless of width or thickness.
Nominal vs Actual Dimensions
This is the single most important concept for accurate board feet calculations. Nominal dimensions are the named size (how the lumber is listed and sold). Actual dimensions are the true milled size after drying and surfacing. Board feet always use nominal dimensions — this is the industry standard.
| Nominal Size | Actual Size | BF per Lin Ft | BF per 8 ft Board | BF per 12 ft Board |
|---|---|---|---|---|
| 1×2 | 0.75″ × 1.5″ | 0.167 BF/ft | 1.33 BF | 2 BF |
| 1×3 | 0.75″ × 2.5″ | 0.25 BF/ft | 2 BF | 3 BF |
| 1×4 | 0.75″ × 3.5″ | 0.333 BF/ft | 2.67 BF | 4 BF |
| 1×6 | 0.75″ × 5.5″ | 0.5 BF/ft | 4 BF | 6 BF |
| 1×8 | 0.75″ × 7.25″ | 0.667 BF/ft | 5.33 BF | 8 BF |
| 1×12 | 0.75″ × 11.25″ | 1.0 BF/ft | 8 BF | 12 BF |
| 2×4 | 1.5″ × 3.5″ | 0.667 BF/ft | 5.33 BF | 8 BF |
| 2×6 | 1.5″ × 5.5″ | 1.0 BF/ft | 8 BF | 12 BF |
| 2×8 | 1.5″ × 7.25″ | 1.333 BF/ft | 10.67 BF | 16 BF |
| 2×10 | 1.5″ × 9.25″ | 1.667 BF/ft | 13.33 BF | 20 BF |
| 2×12 | 1.5″ × 11.25″ | 2.0 BF/ft | 16 BF | 24 BF |
| 4×4 | 3.5″ × 3.5″ | 1.333 BF/ft | 10.67 BF | 16 BF |
Nominal dimensions are the lumber sizes used in all board-feet calculations. Actual dimensions are what you’ll measure with a tape measure on the finished board. Always use nominal (listed) sizes when entering dimensions into this calculator.
Worked Examples
Example 1 — Woodworking Project: Dining Table (Oak)
A dining table top made from 1″ × 6″ red oak boards, 7 ft long, 6 boards wide.
42 ÷ 12 = 3.5 BF per board
Total for 6 boards:3.5 × 6 = 21 BF
Add 15% waste for defects, surfacing, and end cuts:21 × 1.15 = 24.15 BF → order 25 BF
Cost at $7/BF (mid-range red oak):25 × $7 = $175 in lumber
Example 2 — Deck Framing: 2×8 Joists
A deck with 18 pieces of 2″ × 8″ × 12 ft pressure treated joists. Framing lumber is often sold by the piece at big-box stores but priced per BF at wholesale yards.
192 ÷ 12 = 16 BF per joist
Total for 18 joists:16 × 18 = 288 BF
At $1.80/BF wholesale PT lumber:288 × $1.80 = ~$518 wholesale vs $720+ retail per-piece pricing
Tip: For framing lumber orders over 200 BF, check local wholesale lumber yards — per-BF pricing frequently beats big-box per-piece pricing by 20–35%.
Example 3 — Cabinet Shop: Mixed Species Order
A cabinet project requiring multiple species. Board feet lets you compare total cost across species and order precisely from a hardwood dealer.
(1 × 3 × 8) ÷ 12 = 2 BF each × 10 = 20 BF poplar @ $4/BF = $80
Drawer fronts: 8 pcs of 1″ × 6″ × 4 ft cherry(1 × 6 × 4) ÷ 12 = 2 BF each × 8 = 16 BF cherry @ $11/BF = $176
Shelves: 6 pcs of 1″ × 12″ × 6 ft maple(1 × 12 × 6) ÷ 12 = 6 BF each × 6 = 36 BF maple @ $8/BF = $288
Total lumber cost (before waste buffer):$80 + $176 + $288 = $544 · Add 15%: ~$625 budgeted
Board Feet Reference Chart
Quick reference for common lumber sizes. All BF values use nominal dimensions per industry standard.
| Nominal Size | BF per Linear Foot | BF per 8 ft Board | BF per 12 ft Board | BF per 16 ft Board |
|---|---|---|---|---|
| 1×4 | 0.33 BF/ft | 2.67 BF | 4 BF | 5.33 BF |
| 1×6 | 0.5 BF/ft | 4 BF | 6 BF | 8 BF |
| 1×8 | 0.67 BF/ft | 5.33 BF | 8 BF | 10.67 BF |
| 1×12 | 1.0 BF/ft | 8 BF | 12 BF | 16 BF |
| 2×4 | 0.67 BF/ft | 5.33 BF | 8 BF | 10.67 BF |
| 2×6 | 1.0 BF/ft | 8 BF | 12 BF | 16 BF |
| 2×8 | 1.33 BF/ft | 10.67 BF | 16 BF | 21.33 BF |
| 2×10 | 1.67 BF/ft | 13.33 BF | 20 BF | 26.67 BF |
| 2×12 | 2.0 BF/ft | 16 BF | 24 BF | 32 BF |
| 4×4 | 1.33 BF/ft | 10.67 BF | 16 BF | 21.33 BF |
Hardwood Lumber Prices (2026)
Hardwood lumber is universally priced per board foot at US lumber yards and sawmills. Prices vary by region, grade, and whether the wood is rough-sawn, S2S (surfaced 2 sides), or S4S (surfaced 4 sides). These are 2026 US average prices for common-grade lumber.
| Species | Price per BF (2026) | Common Use | Notes |
|---|---|---|---|
| Poplar | $3–$5 | Painted cabinets, painted furniture | Most affordable hardwood; paints very well |
| Pine (Select) | $3–$6 | Shelving, trim, furniture | Common, widely available, easy to work |
| Alder | $4–$7 | Cabinets, stained furniture | Takes stain evenly; popular cabinet species |
| Oak (Red / White) | $5–$9 | Flooring, cabinets, furniture | Most popular hardwood in the US |
| Maple (Hard) | $6–$10 | Flooring, butcher blocks, workbenches | Very hard; excellent for high-wear surfaces |
| Ash | $6–$10 | Tool handles, furniture, sports equipment | Excellent shock resistance |
| Cherry | $8–$14 | Fine furniture, cabinets, millwork | Darkens beautifully with age |
| Walnut | $10–$20 | Premium furniture, gun stocks | Most prized American hardwood |
| Ipe / Teak | $12–$25 | Outdoor decking, marine uses | Extremely durable outdoors; requires no sealing |
| Mahogany (Genuine) | $10–$22 | Boat building, fine furniture | Classic workability; limited availability |
Rough-sawn lumber is the cheapest but requires jointing and planing before use. S2S (surfaced 2 sides) is the most common at hardwood dealers — smooth top and bottom, rough edges. S4S (surfaced 4 sides) is ready-to-use but costs 20–30% more per BF. For most projects, buying S2S and ripping to width yourself saves money. For small hobby projects or occasional woodworkers without a jointer, S4S saves time.
Board Feet vs Linear Feet
Understanding when to use each unit prevents both ordering errors and overpaying.
| Situation | Use Board Feet | Use Linear Feet |
|---|---|---|
| Hardwood lumber (oak, maple, walnut) | Yes — priced per BF at lumber yards | No |
| Framing lumber (2×4, 2×6 studs) | Sometimes (wholesale) | Yes — sold by the piece or LF at big-box |
| Decking boards | Sometimes (wholesale) | Yes — sold by the linear foot at retail |
| Trim / moulding | No | Yes — always sold by LF |
| Sawmill / wholesale lumber order | Yes — all sawmill pricing is per BF | No |
| Custom woodworking quote | Yes — wood shops price by BF | No |
The simple rule: If you’re buying lumber where width and thickness matter to the price (hardwood dealers, sawmills, custom wood shops), use board feet. If you’re buying pre-dimensioned lumber sold per piece or per foot at a home improvement store, use linear feet or just count pieces.
Common Board Feet Calculation Mistakes
Using Actual Dimensions Instead of Nominal
The most common mistake: measuring the board with a tape measure and using 0.75″ and 5.5″ for a 1×6. Board feet calculations use the nominal dimensions (1″ and 6″) regardless of what the tape measure shows. If you use actual dimensions, you’ll underestimate board feet by about 17% for most common sizes — enough to be short on lumber when the project is underway.
Forgetting the 10–15% Waste Buffer
The calculated board feet is the theoretical amount needed with zero waste. Real projects generate waste from: end cuts to remove splits and checks, defects and knots requiring cutouts, ripping boards to exact width, and trimming to final length. Always add 10% for clear, clean lumber with minimal defects; 15% for lumber with some character or for projects with many short pieces; 20% for figured wood or highly selective cutting.
Confusing Board Feet with Square Feet
Board feet include the thickness dimension — square feet do not. A 1×6 board 8 ft long is 4 board feet of volume but covers only 4 sq ft of surface (0.5 ft × 8 ft). A 2×6 board 8 ft long is 8 board feet of volume but also covers only 4 sq ft of surface. Board feet always accounts for thickness; square feet never does.
Length Input in Inches Instead of Feet
The formula uses length in feet, not inches. Entering a 96-inch board as “96” in the length field (instead of 8 ft) produces a result 12 times too large. Always convert length to feet before entering: 96 in ÷ 12 = 8 ft.