Lumber Board Feet Calculator
The Lumber Board Feet Calculator converts the dimensions of your lumber into board feet, the standard unit U.S. lumber yards use for pricing hardwood and specialty wood. In metric mode it reports timber volume in liters and cubic meters instead, since board feet is a U.S.-only unit. Because the calculator multiplies whatever thickness and width you enter, it doesn't automatically convert framing lumber's nominal size (like a "2×6") to its actual milled dimensions (1.5 in × 5.5 in) — using nominal dimensions instead of actual measured ones overstates the true board footage by roughly 40–50% for common dimensional sizes, which matters when you're pricing lumber by the board foot rather than by the piece. Most hardwood dealers also round each board's footage up to the nearest half or whole board foot before pricing, rather than billing on the precise decimal this calculator returns, so expect your invoice to run slightly higher than the raw sum of your individual calculations.
Switch between U.S. Customary and Metric units.
How This Tool Works
Pick your units, then enter the thickness, width, and length of a single board, plus how many pieces you need, to get total board feet (or timber volume in metric).
Formula & Method
Board feet = (thickness in inches × width in inches × length in feet) ÷ 12, multiplied by quantity. In metric, the tool reports timber volume (thickness cm × width cm × length m × quantity) in liters and cubic meters.
Example Calculation
For a rough-sawn board measuring 2 in thick, 7 in wide, and 6 ft long: board feet per piece = (2 × 7 × 6) ÷ 12 = 84 ÷ 12 = 7 board feet. For an order of 3 identical boards: total = 7 × 3 = 21 board feet.
About the Lumber Board Feet Calculator
Walk into a hardwood dealer and ask for a price on walnut, and the answer will come back in dollars per board foot. That unit confuses newcomers because it is not a length and not an area. A board foot is a volume: a piece of wood one inch thick, twelve inches wide, and twelve inches long, or 144 cubic inches. Pricing by volume lets a dealer charge the same rate for a thin wide board and a short thick one that contain the same amount of wood, which is why furniture makers, cabinet shops, and woodworkers use it for rough-sawn and specialty lumber.
The Lumber Board Feet Calculator applies the standard formula: thickness in inches times width in inches times length in feet, divided by twelve. Enter the dimensions of one board, set the quantity, and the tool returns the board feet for a single piece and for the whole order. In metric mode it does not produce board feet, since the unit is used mainly in North America. Instead it reports the volume of timber in liters and cubic meters from thickness and width in centimeters and length in meters.
What the calculator cannot know is how your supplier defines the dimensions. Framing lumber is sold under nominal names such as 2 by 6, but a surfaced board actually measures about 1.5 by 5.5 inches. Hardwoods are often sold by rough thickness in quarters, so a board called 4/4 is a nominal one inch. Understanding which dimensions your dealer uses is the key to getting an estimate that matches the invoice.
When to Use It
Budgeting a hardwood tabletop
A woodworker plans a dining table from rough cherry and needs several boards of the same thickness. He measures the boards at the lumber dealer, calculates the board feet of each, and adds them to estimate the cost at the dealer's per-foot price. He also adds extra for defects, knots, and trimming, since not every inch of a rough board is usable.
Comparing quotes from two suppliers
A cabinetmaker receives quotes from two yards for the same stack of oak, one priced per board foot and the other per piece. By calculating the board footage of each board, she converts both quotes into a price per board foot and sees which supplier is actually cheaper, rather than being swayed by differing board sizes.
Estimating a timber purchase in metric
A builder in a metric country is buying several sawn beams and wants to know the total timber volume for a delivery quote. He enters the thickness and width in centimeters and the length in meters, sets the quantity, and reads the result in cubic meters. The figure can be compared directly with suppliers who price by the cubic meter.
Planning a pergola from heavy posts
A homeowner wants four 8-foot posts for a pergola and wants to know how much lumber that represents before ordering from a specialty mill. By entering the post dimensions and a quantity of four, she gets the total board feet and can compare the price per post with the price per foot, then decide if she should buy solid timber or laminate.
How to Use It, Step by Step
- Pick your units first. U.S. mode takes inches for thickness and width and feet for length, and it returns board feet. Metric mode takes centimeters for thickness and width and meters for length, and it returns volume in liters and cubic meters.
- Enter Thickness for a single board. For rough-sawn hardwood, use the thickness the dealer quotes, such as 1 inch for 4/4 or 2 inches for 8/4. For surfaced framing lumber, use the actual measured thickness.
- Enter Width of the same board, measured across the face. If the dealer prices by the nominal size, you can enter the nominal figure to match the quote, but expect the real volume of wood to be smaller.
- Enter Length. Boards are often sold in random lengths, so measure each one individually or use the length you plan to order. Lengths can be fractional, so 8.5 feet is acceptable.
- Set Quantity to the number of identical boards you need. The default is one, and the field accepts whole numbers up to 10,000. If your order includes different sizes, run each size separately.
- Click Calculate Board Feet and read the per-piece figure and the total. In metric mode the result shows the volume per piece in liters and the total in liters and cubic meters.
- Multiply the total by the price per board foot your supplier quotes, then add an allowance for waste, since defects, saw kerf, and trimming mean you rarely use every inch you buy.
- Add the totals for each size together to find the full order, and check the sum against the supplier's own tally before you pay.
Understanding Your Results
In U.S. mode you see board feet per piece and total board feet. Per-piece figures tell you how much each board contributes to the order, which is useful when you are choosing between several rough boards at the yard. The total is the quantity multiplied by that figure and is the number to multiply by the price per board foot. A value of 8.25 means the wood is equivalent to a little over eight pieces of one-inch by twelve-inch by twelve-inch stock.
In metric mode the tool returns volume per piece in liters and total volume in both liters and cubic meters. One cubic meter holds about 424 board feet, so you can compare a metric supplier's price per cubic meter with a U.S. price per board foot by converting one to the other. The metric result is the straight volume of the dimensions you enter, with no adjustment for the sizes of sawn timber commonly stocked.
Before relying on the number, check that the dimensions match what the dealer uses for pricing. Many yards round each board up to the next half or whole board foot, and some measure width and length to the nearest inch. Waste is another factor. Planning to use 100 percent of what you buy is optimistic, so most woodworkers buy extra, with the amount depending on the species, grade, and the layout of the project.
More Worked Examples
Shelving boards priced by the board foot
Scenario: Twelve boards, each 1 inch thick, 8 inches wide, 10 feet long, U.S. units.
One board is 1 times 8 times 10 divided by 12, which the tool reports as 6.67 board feet. Twelve boards give a total of 80 board feet. At a hypothetical price of $5.00 per board foot the lumber would cost $400 before waste and tax. Because the dimensions are nominal, an actual surfaced one-by-eight is closer to three quarters of an inch by seven and a quarter inches, so the true volume of wood is smaller.
Nominal versus actual 2x6
Scenario: One 2x6 that is 12 feet long, entered first with actual dimensions of 1.5 by 5.5 inches.
With actual dimensions the tool returns 8.25 board feet. Entering the nominal 2 by 6 would give 12 board feet, since 2 times 6 times 12 divided by 12 is 12. The nominal figure overstates the real wood by 3.75 board feet, about 45 percent. This is why you should confirm whether a quote is based on nominal or actual size, especially when comparing framing lumber with hardwood prices.
Sawn timber ordered in metric
Scenario: Twenty pieces, each 5 cm thick, 15 cm wide, and 2.4 m long, metric units.
Each piece has a volume of 18 liters, since 5 times 15 times 240 is 18,000 cubic centimeters. Twenty pieces give a total of 360 liters, which the tool shows as 0.36 cubic meters. If the supplier charges per cubic meter, that is the quantity to multiply by their price. In U.S. terms, 0.36 cubic meters is roughly 150 board feet, a useful comparison when reading catalogs from different regions.
Tips for Better Results
- Ask the dealer whether they price on nominal or actual dimensions and whether they round each board, so the numbers you calculate match what appears on the invoice.
- For rough hardwood, remember that quarter notation describes thickness before surfacing. A board sold as 4/4 is nominally an inch thick, and planing it smooth will reduce it, so buy thicker if you need a specific finished size.
- Add a waste allowance based on the project. Straight-grained boards for simple cuts need less, while projects that demand matched grain, long continuous lengths, or defect-free sections often require noticeably more than the calculated amount.
- Measure each board at the yard instead of assuming random lengths are the same, since width and length can vary and a couple of inches on each piece adds up over a large order.
- Keep a running list of sizes and board feet as you shop. Adding the totals later is easy, and having them written down helps you notice when a supplier's tally does not agree with yours.
- If you buy framing lumber by the piece, use this tool mostly to compare against hardwood prices or to sanity check a quote, because pieces are usually the cheaper unit for standard sizes.
Common Mistakes to Avoid
- Using nominal dimensions for surfaced lumber overstates the amount of wood. Enter the dimensions the supplier uses for pricing, and know that a two-by-four is not actually two inches by four inches.
- Mixing inches and feet leads to errors. In U.S. mode thickness and width are in inches and length is in feet, so a 96-inch board should be entered as 8 feet.
- Entering the quantity for boards of different sizes into one calculation ignores differences. Run each size separately and add the totals.
- Buying exactly the board footage the project requires leaves no margin for defects, knots, and saw kerf. Add an allowance that fits the species and the quality of the boards.
- Reading the metric result as board feet is a mistake. In metric mode the output is volume in liters and cubic meters, and the conversion to board feet requires a separate step.
Assumptions and Limits
- The calculator multiplies exactly the dimensions you enter. It does not convert nominal sizes to actual ones, so the quality of the estimate depends on entering dimensions the way your supplier measures them.
- Each result is the precise decimal board footage. Dealers commonly round each board up to the nearest half or whole board foot, so your invoice may be higher than the raw sum.
- The tool treats every board as a perfect rectangular prism. Tapered, live-edge, or irregular boards need to be measured at their average width and thickness, and the result will be approximate.
- Prices, grades, and measurement customs differ by region and species. For structural lumber, check span tables and code requirements, and ask a lumber dealer or engineer when strength or safety is involved.
Key Terms
- Board foot
- A unit of lumber volume equal to 144 cubic inches, such as a board one inch thick, one foot wide, and one foot long.
- Nominal size
- The name given to a piece of lumber, such as 2 by 4, which is larger than the finished piece after drying and planing.
- Actual size
- The measured dimensions of a finished piece of lumber. A surfaced 2 by 4 measures about 1.5 by 3.5 inches.
- Rough-sawn
- Lumber that has been cut at the mill but not planed, so its surface is coarse and its thickness is close to the nominal figure.
- Quarter notation
- A way of stating hardwood thickness in quarters of an inch, where 4/4 is one inch, 5/4 is one and a quarter inches, and 8/4 is two inches.
- Kerf
- The width of material removed by a saw blade as it cuts, which reduces the usable length or width of a board.
Frequently Asked Questions
What is a board foot?+
A board foot is a unit of volume equal to a piece of wood 12 inches long, 12 inches wide, and 1 inch thick (144 cubic inches).
How do I calculate timber volume in metric?+
Switch the unit toggle to Metric and enter thickness and width in centimeters and length in meters. Board feet is a U.S.-only unit, so metric mode returns the timber volume in liters and cubic meters instead.
Why does lumber use board feet instead of linear feet?+
Board feet account for thickness and width, not just length, which matters for pricing hardwoods sold by volume rather than standard dimensional lumber.
Is nominal or actual lumber size used here?+
Enter whichever dimensions you're quoted — nominal (e.g., "2×6") for framing lumber pricing, or actual measured size for rough-sawn or hardwood lumber.
Why is my calculated board footage different from what my lumberyard charges me?+
Lumberyards typically round each board's footage up to the nearest half or whole board foot for invoicing, rather than billing on the precise decimal this calculator returns. For a single board the difference is small, but it compounds across a large order of odd-sized boards.
Does the quantity field let me total up boards of different sizes?+
No — the quantity field multiplies a single set of dimensions only. If you're ordering boards in several different sizes, run the calculator once per size and add the board-foot totals together yourself.
How many board feet are in a 2x4?+
It depends on the length and on whether you use nominal or actual sizes. A nominal 2 by 4 that is 8 feet long is 2 times 4 times 8 divided by 12, or about 5.33 board feet. Using the actual 1.5 by 3.5 inch size, the same stud contains about 3.5 board feet. Framing lumber is usually sold by the piece or by the linear foot, so board feet matter less than for hardwood.
Why is hardwood sold by the board foot while framing lumber is not?+
Hardwood boards come in many thicknesses, widths, and lengths, so a flat price per piece would be meaningless. Pricing by volume lets a dealer charge consistently across sizes. Framing lumber comes in a small number of standard dimensions that are interchangeable for building, which makes pricing by the piece or by length more convenient. Mills sometimes quote framing in thousands of board feet, but retail customers rarely see that.
How much extra lumber should I buy for waste?+
There is no single answer, since it depends on the species, the grade, the way you cut, and how many defects you can tolerate. A common rule of thumb in woodworking is to buy noticeably more than the calculated amount, often in the range of fifteen to thirty percent for furniture projects that need clear, matched boards. For rough framing with simple cuts, less is typically fine. Ask the yard how they grade their stock.
How do I convert cubic meters of timber to board feet?+
One cubic meter equals about 35.3 cubic feet, and a board foot is one twelfth of a cubic foot, so one cubic meter is roughly 424 board feet. To convert, multiply the cubic meters by 424. For example, the 0.36 cubic meters in the metric example is about 153 board feet. The conversion is approximate because real timber is sold in standard sizes and may be rounded.
Does the calculator work for plywood or sheet goods?+
Technically you can enter a sheet's thickness, width, and length, but it is not the usual way to buy it. Plywood, MDF, and similar panels are sold by the sheet or by area, and prices are set per sheet size and thickness. Use the square footage of the project and divide by the sheet area, with an allowance for waste, to decide how many sheets to buy, rather than board feet.
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