Practical tools for measured work
Board Foot Calculator
Calculate board feet and total cost for dimensional lumber.
How it works
How to use it: enter one board's actual thickness and width in inches and its length in feet, how many identical boards you have, and (optionally) a cost per board foot. All three results update immediately.
Formula. A board foot is a volume unit - a piece 1 inch thick, 12 inches wide and 12 inches (1 foot) long. With thickness and width in inches and length in feet:
Board feet (each) = thickness(in) × width(in) × length(ft) / 12
Total board feet = each × quantity, and Estimated cost = total board feet × cost per board foot.
Worked example. With the defaults above (1 in thick, 8 in wide, 10 ft long, quantity 6, $4.50 per board foot): each board = 1 × 8 × 10 / 12 = 80/12 ≈ 6.67 bd ft; total = 6.67 × 6 = 40.00 bd ft; estimated cost = 40 × $4.50 = $180.00.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Thickness
- 1 in
- Width
- 8 in
- Length
- 10 ft
- Quantity
- 6
- Cost per board foot
- 4.5 $
Primary result: Total: 40.00 bd ft.
Before using the result
- Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
- Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
- When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.
Limitations
Enter the board's actual measured thickness and width, not its nominal size - a nominal "4/4" (one inch) board is typically closer to 13/16″ after surfacing, and a nominal 2×4 measures about 1.5″ × 3.5″ actual. Using nominal dimensions where actual ones apply will overstate the board footage.
This calculates volume only - it does not account for defects, waste from milling to final dimension, or a supplier's minimum-charge or rounding rules (many yards round each board up to the nearest whole board foot, or price in fixed length increments). Use your supplier's stated billing dimensions and rules for a quote that will match their invoice.
Cost per board foot is optional - leave it at 0 to see quantities only.
Frequently asked questions
Should I use nominal or actual lumber dimensions?
Use actual dimensions for an accurate volume - measure the board with a tape or caliper. Nominal sizes (like 4/4 or 2×4) are trade names for a rough-sawn starting size and are larger than the surfaced board you actually receive.
How is a board foot different from a linear foot?
A linear foot measures length only, regardless of thickness or width. A board foot measures volume, so a wide, thick board and a narrow, thin board of the same length can have very different board-foot totals - that's why lumber is priced by the board foot rather than the linear foot.
Will this match what my lumber yard charges me?
It should be close, but yards often round each board's footage up (for example to the nearest whole or half board foot) and price by grade and species on top of raw volume. Treat this as an estimate and confirm against your supplier's invoice method.
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