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Board foot calculator. Board feet, waste and cost for a cut list.

A board foot is 144 cubic inches of lumber, thickness × width × length in inches ÷ 144, and this calculator adds up a whole cut list with waste and cost.

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Units
Cut list

Thickness takes quarters (4/4, 5/4, 8/4), fractions or decimals. Length takes feet (8, 8.5) or feet and inches (8' 6").

Assumption: 15% for defects, offcuts and milling. Use your own figure.

01— Method

How to calculate board feet

Thickness × width × length in inches, divided by 144, for each piece; then quantity, waste and price. Five steps, and what this calculator does with each.

  1. 01Measure in inches

    Board feet are defined in inches: a board 1 in thick, 12 in wide and 12 in long is one board foot. Hardwood is sold by nominal rough thickness in quarters: 4/4 is 1 in, 5/4 is 1¼ in, 8/4 is 2 in.

    This tool: reads quarters, fractions and decimals for thickness, and feet or feet and inches for length.

  2. 02Multiply and divide by 144

    Thickness × width × length, all in inches, divided by 144 gives one piece’s board feet. With the length in feet, divide by 12 instead.

    This tool: does it for every row, so 1 × 6 in × 8 ft is 4 board feet.

  3. 03Multiply by the quantity and add the rows

    A cut list is a set of identical pieces per row. Each row’s board feet times its quantity, summed, is the net volume the project uses.

    This tool: totals every row it can read and flags the ones it cannot, without dropping them silently.

  4. 04Add a waste allowance

    Defects, knots, end checks, offcuts and milling all eat lumber, so buyers add a percentage on top of the net figure. How much depends on the species, the grade and the parts.

    This tool: starts at 15%, an assumption you should replace with your own shop’s figure.

  5. 05Price what you buy

    Lumber yards price hardwood per board foot, so the cost is the board feet you buy, waste included, times the price.

    This tool: multiplies your price by the board feet with waste, or in metric your price per m³ by the m³ with waste. It has no prices of its own.

02— FAQ

Questions about the board foot calculator.

What it does, what it leaves to you, and what it costs.

A unit of lumber volume: 144 cubic inches, the volume of a board 1 in thick, 12 in wide and 12 in long. One board foot is 0.00236 cubic meters.

Type it as written. Quarter notation is a fraction of an inch, so 4/4 is read as 1 in, 5/4 as 1.25 in and 8/4 as 2 in. Decimals (0.75) and mixed numbers (1 1/4) work too.

Hardwood is bought by its nominal rough size (a 4/4 board is billed as 1 in thick even after it is surfaced thinner), so use the size the yard bills by. For softwood dimensional lumber, a 2×4 is billed on its nominal 2 × 4 in, not the actual 1.5 × 3.5 in. The calculator uses whatever numbers you give it.

It is a starting assumption, not a rule: the right figure depends on species, grade and how many short or narrow parts the cut list has. Change it to your shop’s own number (15 and 15% both work); set it to 0 to see the net board feet only.

Yes, second to cubic meters. Enter thickness and width in millimeters and length in meters; the result leads with cubic meters, to buy and net, and shows the same volume in board feet (1 board foot is 144 cubic inches, about 0.00236 m³). The optional price is per m³. Switching units converts the cut list (inches to mm, feet to m); a row that cannot be converted is cleared, and the switch can be undone.

No. It totals volume, waste and cost. It does not lay parts out on boards or account for kerf, grain direction or the lengths your yard stocks.

Free, with no sign-up. The arithmetic runs in your browser and nothing is sent to a server or saved; the cut list lives only in the page address, so copying the link (or Share) passes it on.

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