Board Foot Calculator
Estimate lumber volume in board feet, compare the volume of one board with the full order, and calculate an optional purchase cost.
Board dimensions and price
Required whole number from 1 to 1,000,000.
Required actual or nominal thickness in inches.
Required board width in inches.
Required board length in feet.
Optional U.S. dollars per BF; leave blank to omit cost.
Live results
Volume for all boards in the order.
Calculation detail
| Measure | One board | Full order | Unit |
|---|---|---|---|
| Volume | 8.3333 | 41.6667 | board feet |
| Volume | 1,200.00 | 6,000.00 | cubic inches |
| Volume | 0.6944 | 3.4722 | cubic feet |
| Estimated cost | $34.58 | $172.92 | U.S. dollars |
How to use this board foot calculator
What this calculator does
This calculator estimates the board-foot volume of a group of identical rectangular lumber boards and, when a price is supplied, the estimated purchase cost. A board foot is the volume represented by a board 1 foot long, 1 foot wide, and 1 inch thick – equivalent to 144 cubic inches. The calculation is useful for dimensional lumber and hardwood sold by board footage. It does not estimate the yield from a round log, account for saw kerf, grade, moisture movement, waste, surfacing allowances, or mixed board sizes. The NIST method-of-sale definition for hardwood lumber provides the regulatory context for the unit.
When to use it
Use the calculator when pricing a stack of same-size hardwood boards, checking a supplier tally, planning material for furniture or cabinetry, or converting a board list into a comparable volume. For mixed sizes, calculate each size group separately and add the board-foot totals.
How to calculate
- The calculator opens with a complete demonstration: 5 boards, each 1.25 inches thick, 10 inches wide, and 8 feet long, priced at $4.15 per board foot. The example results and a validated Excel workbook are available immediately.
- Replace Number of boards, Thickness, Width, and Length with your measurements. Keep thickness and width in inches and length in feet.
- Enter Price per board foot in U.S. dollars to calculate cost, or leave it blank when volume alone is needed.
- Read Total board footage first, then use the per-board, cubic-volume, cost, and detail-table outputs as checks.
- Select Download Excel to export the current validated inputs and results. Reset clears the demonstration and all entered data; it may disable Excel export until a complete valid set of dimensions is entered again.
Input guide
Number of boards is a required whole count from 1 to 1,000,000; for example, 5. Increasing it scales the total volume and cost proportionally. Fractions, zero, and negative counts are rejected. Thickness is a required positive decimal in inches, such as 1.25. Width is also required in inches, such as 10. Length is required in feet, such as 8. Each dimension multiplies the result directly, so doubling any one dimension doubles board footage. Use the dimension basis used by your seller – nominal and actual surfaced sizes are not interchangeable. Price per board foot is optional and accepts a nonnegative U.S. dollar amount such as 4.15. It changes cost only, not volume. Commas, currency symbols, percentages, scientific notation, and decimal-comma forms are intentionally rejected to prevent ambiguous input.
Output guide
Total board footage is the estimated volume for the entire order in BF and is the primary planning number. Board feet per board isolates one identical board. Total cost multiplies total BF by the optional price; it displays “Not priced” when the price is blank. Cubic inches and Cubic feet are exact volume conversions from the same dimensions and can help cross-check units, but they do not replace a seller's board-foot tally. The summary pills repeat board count, per-board volume, and order volume. In the Calculation detail table, One board and Full order show the same canonical model in board feet, cubic inches, cubic feet, and estimated cost. Zero is not accepted for required dimensions because a zero-volume board is not meaningful for this purchasing workflow.
Worked example
The startup board has a volume of 8 ft × 10 in × 1.25 in = 100 in²·ft. Dividing by 12 converts that mixed-unit product to board feet: 100 ÷ 12 = 8.3333 BF per board. For 5 boards, 8.3333 × 5 = 41.6667 BF, displayed as 41.67 BF. At $4.15/BF, the estimated cost is 41.6667 × $4.15 = $172.92. Those values match the first-open results and workbook checkpoints.
Formula and measurement basis
Total board feet = board feet per board × number of boards
The factor 12 appears because a board foot contains 12 square inches of cross-sectional area carried through one linear foot. Equivalently, calculate total cubic inches and divide by 144. NIST's Uniform Laws and Regulations handbook defines one board foot as 144 cubic inches for hardwood lumber retail sales. The American Softwood Lumber Standard also explains why nominal dimensions and dressed dimensions require care in commercial measurement.
Planning cautions
Board footage is not a cutting-list allowance. Add a project-specific waste factor separately for defects, grain matching, trimming, and machining. Also confirm the seller's tally convention before comparing invoices.
Logs require scaling rules rather than the rectangular-board formula. The USDA Forest Service's collection of log rules describes why estimated lumber yield from round logs depends on the chosen rule and assumptions. For finished boards, measure consistently, retain more precision during planning, and round only the final purchasing figure according to the supplier's practice.