Board Foot Calculator
Calculate exact board feet (BF), lumber volume, and total project timber cost for hardwood and softwood with waste factor allowances.
| Volume per Single Board | 6.67 BF |
| Net Usable Board Footage | 33.33 BF (5 pcs) |
| Waste & Kerf Allowance | +5.00 BF (15%) |
| Total Gross Board Feet Needed | 38.33 BF |
| Total Estimated Material Cost | $287.50 |
| Net Usable Material Cost | $250.00 |
| Waste Material Cost | $37.50 |
| Total Linear Footage | 50.0 linear ft |
| Total Solid Volume | 3.19 cu ft (0.090 m³) |
Common Lumber Dimensions & Board Footage Reference
Standard board foot yields across popular lumber sizes and standard commercial lengths.
| Nominal Size | Actual Size (S4S) | 8 ft Length | 10 ft Length | 12 ft Length | 16 ft Length | Primary Application |
|---|---|---|---|---|---|---|
| 1 × 4 (4/4 × 4) | ¾" × 3½" | 2.67 BF | 3.33 BF | 4.00 BF | 5.33 BF | Trim, fascia, face frames, slats |
| 1 × 6 (4/4 × 6) | ¾" × 5½" | 4.00 BF | 5.00 BF | 6.00 BF | 8.00 BF | Cabinetry, shelving, paneling |
| 1 × 8 (4/4 × 8) | ¾" × 7¼" | 5.33 BF | 6.67 BF | 8.00 BF | 10.67 BF | Furniture sides, casework, shelving |
| 1 × 10 (4/4 × 10) | ¾" × 9¼" | 6.67 BF | 8.33 BF | 10.00 BF | 13.33 BF | Wide casework, deep shelves, stair risers |
| 1 × 12 (4/4 × 12) | ¾" × 11¼" | 8.00 BF | 10.00 BF | 12.00 BF | 16.00 BF | Tabletops, instrument bodies, broad panels |
| 5/4 × 6 Decking | 1" × 5½" | 5.00 BF | 6.25 BF | 7.50 BF | 10.00 BF | Outdoor decking, porch flooring, treads |
| 2 × 4 Stud | 1½" × 3½" | 5.33 BF | 6.67 BF | 8.00 BF | 10.67 BF | Wall framing, structural studs, trusses |
| 2 × 6 Joist | 1½" × 5½" | 8.00 BF | 10.00 BF | 12.00 BF | 16.00 BF | Floor joists, ceiling rafters, headers |
| 2 × 8 Plank | 1½" × 7¼" | 10.67 BF | 13.33 BF | 16.00 BF | 21.33 BF | Subflooring, heavy rafters, deck beams |
| 2 × 10 Joist | 1½" × 9¼" | 13.33 BF | 16.67 BF | 20.00 BF | 26.67 BF | Floor joists, commercial headers, stair stringers |
| 2 × 12 Beam | 1½" × 11¼" | 16.00 BF | 20.00 BF | 24.00 BF | 32.00 BF | Ridge beams, major headers, stair carriages |
| 8/4 × 8 Hardwood | 1¾" (surfaced) | 10.67 BF | 13.33 BF | 16.00 BF | 21.33 BF | Dining table tops, workbench tops, turnings |
About the Board Foot Unit
A board foot (abbreviated BF or FBM for "foot board measure") is the North American timber industry's standard volumetric unit for measuring rough-sawn and milled lumber. One board foot represents a volume equivalent to a board that is 1 inch thick, 12 inches wide, and 12 inches (1 foot) long, totaling 144 cubic inches (or 1/12 of a cubic foot / approximately 0.00236 cubic meters).
Unlike linear feet (which only records length) or square feet (which only measures surface area), board footage measures total timber mass. This volumetric pricing model protects both sawmills and woodworkers: a thick 8/4 slab containing twice the wood fiber of a 4/4 board of the same length and width is accurately priced at twice the board footage.
Mathematical Formulas & Calculation Steps
Depending on how your measurements are taken, use the corresponding formula:
BF = [T (in) × W (in) × L (ft)] ÷ 12
Multiply thickness in inches by width in inches by length in feet, then divide by 12.
BF = [T (in) × W (in) × L (in)] ÷ 144
When measuring short cut-offs or furniture components completely in inches, divide by 144.
BF = [T (mm) × W (mm) × L (m)] ÷ 2,359.74
Converts metric cubic volume (m³) directly into international board feet.
How to Use This Calculator
Specify the thickness and width in inches (or use the quick quarter-sizing chips like 4/4 or 8/4), then set your board length in feet or inches.
Enter the number of boards you need. In "+ More Options", adjust your waste allowance (typically 15% for cabinetry or 20% for rough boards).
Input your lumber yard's price per board foot ($/BF) to instantaneously view net and gross lumber volume, total cost, linear feet, and cubic feet.
Why Woodworkers & Builders Use a Board Foot Calculator
- Accurate Sawmill Invoicing: Hardwood lumber yards do not sell by the piece or linear foot. Knowing your exact board footage prevents overcharges at the checkout counter.
- Preventing Project Shortfalls: Factoring in 15% to 20% waste for jointer and planer milling, knots, splits, and saw kerf ensures you never run out of matching grain in the middle of a build.
- Comparing Material Budgets: Accurately calculate the true cost difference between domestic hardwoods (e.g. Poplar at $4.00/BF vs Walnut at $13.50/BF) before purchasing.
Key Industry Terms & Definitions
| Lumber Term | Definition & Practical Application |
|---|---|
| Quarter Sizing (4/4, 8/4) | The traditional hardwood thickness system in quarters of an inch. 4/4 is 1" thick; 5/4 is 1¼"; 6/4 is 1½"; 8/4 is 2". Surfaced wood is thinner, but billed at nominal rough quarters. |
| S2S / S4S | Surfacing designations: S2S means "Surfaced 2 Sides" (planed top and bottom to consistent thickness). S4S means "Surfaced 4 Sides" (planed smooth on both faces and both edges). |
| Saw Kerf | The width of material turned into sawdust by a saw blade (typically 1/8" for standard table saw blades). Repeated cuts consume substantial board footage over a project. |
| Kiln-Dried (KD) | Lumber dried in a heated kiln to a target moisture content of 6% to 8% for interior furniture use, minimizing future warping, cupping, or checking. |