Board Feet Calculator
A board foot (BF) is the standard unit for measuring lumber volume: one board foot equals a piece of wood 1 inch thick, 12 inches wide, and 1 foot long. Use this calculator to find board feet per piece, total board feet for multiple pieces, and estimated material cost. Select a nominal lumber preset (2×4, 1×6, etc.) to auto-fill actual dimensions, or enter custom measurements.
Calculate Board Feet
Enter the dimensions of your lumber to calculate board feet. Use the nominal presets to auto-fill actual dimensions.
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Frequently Asked Questions
What is a board foot?
A board foot (BF) is the standard unit of lumber volume in the United States and Canada. One board foot equals a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long — equivalent to 144 cubic inches. Board feet are used by lumber yards, sawmills, and woodworkers to price and measure lumber. Unlike linear feet (length only) or square feet (area only), board feet capture all three dimensions: thickness, width, and length.
How do you calculate board feet?
Board feet are calculated using the formula: Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. For example, a board that is 2 inches thick, 6 inches wide, and 8 feet long contains (2 × 6 × 8) ÷ 12 = 8 board feet. If all dimensions are in inches, divide by 144 instead: (Thickness × Width × Length in inches) ÷ 144. For multiple pieces, multiply the board feet per piece by the number of pieces.
What is the difference between nominal and actual lumber dimensions?
Nominal dimensions are the labeled sizes used to identify lumber (e.g., '2×4', '1×6'), while actual dimensions are the true measured size after the wood has been dried and surfaced. A nominal 2×4 actually measures 1.5 inches by 3.5 inches — about 25% smaller in each dimension. This reduction happens during kiln-drying and surface planing at the mill. For board foot calculations, use actual dimensions for dressed (surfaced) lumber and nominal dimensions for rough-sawn lumber.
How many board feet are in a 2×4×8?
A nominal 2×4 at 8 feet long contains (2 × 4 × 8) ÷ 12 = 5.33 board feet using nominal dimensions. Using actual dimensions (1.5″ × 3.5″), it contains (1.5 × 3.5 × 8) ÷ 12 = 3.5 board feet. The difference matters: lumber yards typically price hardwoods by actual board feet, while softwood construction lumber is often sold by the linear foot or piece at a fixed price rather than priced per board foot.
How much does lumber cost per board foot?
Lumber prices per board foot vary widely by species, grade, and market conditions. Common softwoods like pine, spruce, and fir used for construction run $0.75–$2.00 per board foot. Cedar and pressure-treated pine for decking cost $1.25–$5.00 per board foot. Popular hardwoods like oak and maple range from $4–$10 per board foot. Premium hardwoods like walnut and cherry cost $8–$20 per board foot, and exotic species like teak can exceed $40 per board foot.
How do I calculate how much lumber I need for a project?
First, list every lumber component in your project with its thickness, width, length, and quantity. Calculate the board feet for each component using the formula (T × W × L) ÷ 12, then multiply by the number of pieces. Sum all the results to get your total board feet. Add a waste factor of 10–15% for typical projects, or up to 20% for hardwood projects with more cutting and fitting. For large projects, consider adding extra for defects and measurement errors.
Can I use board feet to calculate lumber costs?
Yes. Once you know the total board feet for your project, multiply by the price per board foot to estimate material cost: Total Cost = Total Board Feet × Price per Board Foot. For example, 50 board feet of red oak at $6.50/BF would cost approximately $325. Be sure to add your waste factor before calculating cost. Also note that lumber prices fluctuate with market conditions — always verify current prices with your supplier before finalizing your budget.
What is a board foot vs a linear foot vs a square foot?
A linear foot measures length only (1 foot = 1 linear foot), used for trim, molding, and simple length-based pricing. A square foot measures area (length × width), used for flooring, siding, and sheet goods. A board foot measures volume (thickness × width × length), used for dimensional lumber pricing. One board foot of 1-inch-thick lumber covers 1 square foot; 2-inch-thick lumber yields only 0.5 square feet per board foot. Board feet are the most complete measure because they account for all three dimensions.
Understanding Board Feet
What is a Board Foot?
A board foot (BF or FBM — feet board measure) is the standard unit of volume for lumber in the United States and Canada. One board foot equals a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long — in other words, 144 cubic inches of wood.
Board feet are used by lumber yards, sawmills, and woodworkers to price and measure rough-cut and dimensional lumber. Unlike linear feet (which measure length only) or square feet (which measure area), board feet account for all three dimensions — thickness, width, and length — making them a true volumetric measure.
When buying lumber in bulk, suppliers price wood per board foot. Knowing how to calculate board feet lets you accurately estimate material costs for decks, furniture, cabinetry, framing, and any other woodworking or construction project.
Board Foot Formula
The board foot formula is straightforward. You need the thickness in inches, the width in inches, and the length in feet:
Primary Formula (length in feet):
Board Feet = (Thickness" × Width" × Length') ÷ 12
Alternative Formula (all dimensions in inches):
Board Feet = (Thickness" × Width" × Length") ÷ 144
Total for Multiple Pieces:
Total Board Feet = Board Feet per Piece × Number of Pieces
Worked Examples
Example 1: Standard 1×12 at 8 feet
A 1×12 board (actual 0.75″ × 11.25″) at 8 feet long:
(0.75 × 11.25 × 8) ÷ 12 = 67.5 ÷ 12 = 5.625 BF
Example 2: Ten 2×6 studs at 10 feet
A 2×6 (actual 1.5″ × 5.5″) at 10 feet, 10 pieces:
(1.5 × 5.5 × 10) ÷ 12 = 82.5 ÷ 12 = 6.875 BF each × 10 = 68.75 BF total
Example 3: Rough-sawn lumber 2″ × 8″ × 12 feet
Using nominal dimensions for rough-sawn stock:
(2 × 8 × 12) ÷ 12 = 192 ÷ 12 = 16 BF
Nominal vs Actual Dimensions
One of the most common sources of confusion in lumber purchasing is the difference between nominal and actualdimensions. When you buy a "2×4" from a lumber yard, it does not actually measure 2 inches by 4 inches.
Nominal sizes refer to the rough-cut green lumber dimensions before drying and surfacing. The drying process (kiln-drying) and surface planing reduce the wood's size. The result is that dressed (surfaced) lumber is consistently smaller than its nominal label.
For board foot calculations, you should use the actual dimensions when working with dressed lumber, and the nominal dimensions when working with rough-sawn lumber (which retains more of its original size).
| Nominal Size | Actual Thickness | Actual Width | Reduction |
|---|---|---|---|
| 1×4 | 0.75″ | 3.5″ | ~30% |
| 1×6 | 0.75″ | 5.5″ | ~31% |
| 1×8 | 0.75″ | 7.25″ | ~30% |
| 1×10 | 0.75″ | 9.25″ | ~31% |
| 1×12 | 0.75″ | 11.25″ | ~30% |
| 2×4 | 1.5″ | 3.5″ | ~31% |
| 2×6 | 1.5″ | 5.5″ | ~31% |
| 2×8 | 1.5″ | 7.25″ | ~30% |
| 2×10 | 1.5″ | 9.25″ | ~31% |
| 2×12 | 1.5″ | 11.25″ | ~30% |
| 4×4 | 3.5″ | 3.5″ | ~25% |
| 6×6 | 5.5″ | 5.5″ | ~17% |
Note: Rough-sawn lumber may be closer to nominal dimensions. Always measure your actual lumber before calculating for critical projects.
Common Lumber Sizes & Applications
Understanding which lumber sizes are standard for different applications helps you estimate materials more efficiently and avoid costly over- or under-ordering.
Framing Lumber
- 2×4 (1.5″ × 3.5″): Standard wall studs, spaced 16″ or 24″ on center. Most common framing member.
- 2×6 (1.5″ × 5.5″): Exterior walls for better insulation, floor joists for shorter spans.
- 2×8 (1.5″ × 7.25″): Floor joists, ceiling joists, rafters for medium spans.
- 2×10 (1.5″ × 9.25″): Floor joists and rafters for longer spans, stair stringers.
- 2×12 (1.5″ × 11.25″): Longer span floor joists, headers, stair stringers.
Decking & Outdoor
- 5/4×6 (1″ × 5.5″): Standard decking board, slightly thicker than 1×6 for better durability.
- 2×6: Decking for heavier loads or wider spacing between joists.
- 4×4 (3.5″ × 3.5″): Deck posts for standard-height decks up to about 6 feet.
- 6×6 (5.5″ × 5.5″): Deck posts for tall decks, pergola columns, heavy-duty applications.
Finish & Trim
- 1×4 (0.75″ × 3.5″): Baseboards, door casings, cabinet face frames, shelf cleats.
- 1×6 (0.75″ × 5.5″): Wide baseboard, wainscoting, cabinet sides, shelving.
- 1×8 (0.75″ × 7.25″): Wide shelving, furniture panels, drawer fronts.
- 1×10 & 1×12: Wide shelves, furniture tops, cabinet panels, stair treads.
Lumber Pricing Guide
Lumber prices fluctuate with market conditions, species, grade, and treatment. The following ranges reflect typical retail prices per board foot in the United States as of 2025–2026, and are intended as planning estimates only. Always get current quotes from your local lumber yard or home center.
| Species / Type | Typical $/BF | Common Uses |
|---|---|---|
| Construction Pine / SPF | $0.75 – $1.50 | Framing, sheathing |
| Douglas Fir | $1.00 – $2.00 | Framing, structural beams |
| Pressure-Treated Pine | $1.25 – $2.50 | Decks, ground contact |
| Cedar (Western Red) | $2.50 – $5.00 | Decking, fencing, siding |
| Poplar (Hardwood) | $2.00 – $4.00 | Furniture, cabinets (painted) |
| Oak (Red / White) | $4.00 – $8.00 | Furniture, flooring, cabinets |
| Maple (Hard) | $5.00 – $10.00 | Countertops, cutting boards, flooring |
| Cherry | $6.00 – $12.00 | Fine furniture, cabinets |
| Walnut | $8.00 – $20.00 | Premium furniture, gun stocks |
| White Ash | $4.00 – $8.00 | Tool handles, sports equipment, furniture |
| Teak | $20.00 – $40.00 | Marine, outdoor furniture, premium decking |
Grade matters: Select-grade (clear) lumber commands a significant premium over common or construction grades due to fewer knots and defects.
Bulk discounts: Buying full units or lifts from a sawmill or specialty supplier can reduce costs by 20–40% compared to retail home centers.
Waste factor: Add 10–15% to your board foot calculation to account for cuts, defects, and mistakes — especially for furniture and finish work where material quality is critical.