Board Foot Calculator

What Is a Board Foot? The Standard Unit for Lumber Volume

A board foot is the standard unit of measurement for lumber volume in the United States and Canada. It equals the volume of a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long — exactly 144 cubic inches, or one-twelfth of a cubic foot. The board foot is used universally in the lumber and hardwood trades because it accounts for all three dimensions of a board simultaneously, allowing fair price comparisons across pieces of very different sizes.

The formula is simple and always the same:

Board Feet = (Thickness inches × Width inches × Length feet) ÷ 12

A 1×6 board that is 8 feet long contains (1 × 6 × 8) / 12 = 4 board feet. A 2×6 at 8 feet contains (2 × 6 × 8) / 12 = 8 board feet — exactly twice as much wood as the 1×6 of the same width and length, because it is twice as thick. A 1×12 at 8 feet contains (1 × 12 × 8) / 12 = 8 board feet — the same as the 2×6, because it has the same total cross-sectional area.

This volume-based measurement is what makes board feet so useful: if a dealer quotes $8 per board foot for Red Oak, that price applies equally to a thin wide board and a thick narrow board, because both contain the same amount of wood per board foot.

Hardwood dealers, specialty lumber yards, sawmills, and wholesale lumber distributors almost always price by the board foot. Home improvement stores often price softwood dimensional lumber (2×4s, 2×6s) by the linear foot or by the piece, but when comparing value or planning larger orders, knowing the board foot count is essential.

Nominal vs. Actual Dimensions: Why the Formula Uses Nominal Sizes

One of the most important things to understand about the board foot formula is that it uses nominal dimensions — the labeled size — rather than the actual (dressed) dimensions of the board. A 1×6 pine board actually measures about 3/4 inch × 5-1/2 inches after milling, but the formula uses 1 × 6. A 2×4 stud actually measures 1-1/2 inches × 3-1/2 inches, but the formula uses 2 × 4.

This convention is a long-standing industry practice. Lumber was historically sold in its rough-sawn state, graded and priced by nominal size. When mills began surfacing (planing) lumber as a standard practice in the early 20th century, the nominal size labels were retained for continuity even as the actual dimensions shrank. Every lumber dealer calculates board feet using nominal dimensions, so this calculator matches the industry convention.

Exception for rough-sawn lumber: If you are buying rough-sawn hardwood that has not been surfaced, enter the actual rough-sawn measurements — for example, a rough board that measures 1-1/8 inches by 7 inches would be entered as 1.125 × 7. Rough lumber is sold at its actual rough size, not at a nominal size. Leave the "Use nominal dimensions" checkbox unchecked in this case.

Hardwood Lumber Thickness: The Quarter System

Hardwood lumber uses a quarter-inch system to describe thickness. Instead of saying "1 inch thick," a hardwood dealer says "4/4" (four-quarter). Each quarter represents 1/4 inch of rough-sawn thickness. This system describes the rough (unsurfaced) thickness of the board as it comes from the sawmill:

When entering hardwood thickness in this calculator, enter the rough-sawn thickness (the number in the numerator ÷ 4). For 4/4 lumber enter 1 inch, for 8/4 enter 2 inches. The board foot calculation will be correct for the rough-sawn stock you are purchasing and paying for. After surfacing, you will have less thickness — but you bought and paid for the rough size, so that is the size to use in the formula.

Wood Species Comparison: Price, Hardness, and Best Uses

Wood species choice is the single biggest driver of material cost in a woodworking project. A walnut dining table will cost three to four times as much in materials as the same table built from poplar — and the cost difference is almost entirely in the price per board foot. Here is a detailed comparison of the ten species in this calculator:

Softwoods (Lower Cost)

Common Pine ($3.00–$4.50/BF) is the most affordable wood for projects. Easy to cut, nail, and glue. Tends to have knots and grain variation that add character to rustic furniture. Not suitable for high-wear surfaces because it is soft. Excellent for painted furniture, beginner projects, and construction lumber.

Select Pine ($4.50–$6.00/BF) offers clearer grain with fewer and smaller knots. Still a softwood, still easy to work. Better for natural-finish furniture where a consistent appearance matters. Stains somewhat inconsistently without pre-stain conditioner.

Cedar ($5.00–$7.50/BF) is naturally rot and insect resistant — the classic wood for cedar chests, closet lining, and outdoor furniture. Very light (low density) so it dents easily but is easy to work. Its aromatic oils repel moths and insects, making it ideal for blanket chests and wardrobes.

Mid-Range Hardwoods

Poplar ($4.00–$6.00/BF) is technically a hardwood but is soft and easy to work. The best choice for painted furniture and cabinet interiors where appearance does not matter. Takes paint better than almost any other wood. Has greenish and purple streaks in the grain that look unusual without paint, making it unsuitable for natural-finish projects.

Red Oak ($7.00–$9.00/BF) is the most popular hardwood in North America. Strong, stiff, and hard. Open grain absorbs stain evenly, making it excellent for furniture and flooring where a stained finish is desired. Widely available and moderately priced. Classic choice for traditional furniture, cabinets, and hardwood flooring.

Hard Maple ($7.50–$10.00/BF) is one of the hardest domestic species — ideal for workbenches, butcher blocks, and any high-wear surface. Its tight, consistent grain can be difficult to stain evenly; usually finished with oil, lacquer, or clear coats to highlight its natural figure. The classic wood for bowling lanes and gym floors.

Premium Hardwoods

White Oak ($8.50–$11.00/BF) differs from Red Oak in having a tighter, more closed grain and stronger natural rot resistance due to tyloses in the vessels. It is the traditional barrel wood, boat wood, and the preferred species for contemporary and Craftsman-style furniture. Has a more subtle, gray-brown tone compared to the warmer pink-red of Red Oak.

Cherry ($9.00–$12.00/BF) is a traditional American fine furniture wood. It starts out pinkish-tan and darkens over years of light exposure to a rich reddish-amber color. Machines very cleanly, takes oil finishes beautifully, and ages in a way that increases its beauty. One of the premier domestic cabinet and furniture woods.

Black Walnut ($10.00–$15.00/BF) is the premium domestic hardwood. Its deep chocolate-brown heartwood, natural luster, and excellent workability make it the preferred choice for heirloom furniture, gun stocks, and jewelry boxes. It commands the highest price of the common domestic hardwoods. Figured walnut — with curly, crotch, or burl figure — can cost significantly more.

Waste Factor: How Much Extra Lumber to Buy

The waste factor is one of the most important variables in any lumber estimate. Buying too little means a frustrating return trip to the lumber yard mid-project. Buying too much wastes money and creates excess inventory. The right waste percentage depends on the nature of your project:

10% Waste — Simple Projects

Use 10% for projects with mostly full-length boards, few cross-cuts, and straightforward construction: basic shelving where boards run their full length, simple boxes or crates, rough-sawn slabs used nearly as-is. The 10% covers minor end trimming, one or two measurement errors, and any boards with small defects that must be cut out.

15% Waste — Typical Furniture and Cabinets

Use 15% for most furniture projects: tables, chairs, cabinets, and bookcases where you are cutting multiple parts from each board. Cross-cuts, rip cuts, and joinery all produce short cutoffs and saw kerfs that add up. A dining table with six legs, aprons, and a multi-board top will easily lose 12–18% of raw material to saw kerfs, snipe from the planer, and end trimming.

20–25% Waste — Complex Designs and Figured Wood

Increase to 20–25% for projects with many curved parts cut from straight boards, complex joinery with tight tolerances, or boards with significant figure or character that requires working around defects. If you are buying highly figured wood — curly maple, bird's eye maple, or crotch-figure walnut — you may need to buy 25–30% more than you need because the desirable figure may not extend through the full length or width of every board.

Rough-Sawn Surfacing Loss

If you are buying rough-sawn lumber and surfacing it yourself or having it surfaced, add another 10–15% on top of your project waste to account for surfacing losses. Jointing a face removes 1/16 to 1/8 inch. Planing to thickness removes material from the second face. Jointing an edge and ripping to width removes more. A 4/4 rough-sawn board (nominally 1 inch) may yield only 11/16 to 3/4 inch of finished thickness after full surfacing — a 20% loss in thickness that proportionally reduces your usable board footage.

Buy Long Boards for Efficiency

One of the best ways to reduce waste is to buy boards as long as practical. A 10-foot board gives you more flexibility to lay out parts efficiently and minimize end cuts than two 5-foot boards. Long boards also let you choose which end of the board to start cutting from, allowing you to work around any checks, splits, or discolored end-grain at the tips.

How to Buy Hardwood Lumber: Grades, Sources, and What to Look For

Unlike dimensional softwood lumber which comes in standard sizes, hardwood lumber is typically sold in random widths and lengths. You select individual boards from the dealer's inventory based on the width, length, thickness, figure, and grade that your project requires. Understanding the grading system helps you buy the right material at the right price.

NHLA Hardwood Grades

The National Hardwood Lumber Association (NHLA) governs the grading rules for hardwood lumber in North America. The grades, from highest to lowest, are:

• FAS (Firsts and Seconds): The highest grade. Boards must yield at least 83-1/3% clear wood in cuttings on the poorer face. Minimum size is 6 inches wide by 8 feet long. Best for projects requiring long, wide, clear panels — furniture tops, cabinet doors, architectural millwork.
• FAS-1-Face (F1F): FAS on one face, No. 1 Common on the other. Often a great value for projects where only one face shows, such as cabinet face frames or tabletop panels glued up with one face down.
• No. 1 Common (1C): Boards yield at least 66-2/3% clear wood. Smaller minimum size (3 inches wide by 4 feet long). Excellent value for projects using shorter, narrower parts — chair components, drawer sides, small cabinet boxes.
• No. 2 Common (2C): Boards yield at least 50% clear wood. More knots and character marks. Best for rustic furniture, painted projects, or applications where the full natural character of the wood is desired.

Where to Buy Hardwood Lumber

Specialty hardwood dealers are the best source for furniture-grade hardwoods. They carry a wide selection of species, grades, and thicknesses, allow hand-selection of individual boards, and can provide milling services (surfacing, straight lining, ripping). Prices are fair and staff knowledge is excellent.

Sawmills and small operations can be an excellent source for rough-sawn lumber, often at lower prices than dealers. Local sawmills may offer species and figures not available at retail. You pay for rough stock and do your own surfacing.

Online lumber retailers have expanded significantly in recent years. Sites like Bell Forest Products, Woodcraft, and Certainly Wood allow ordering by the board foot with detailed photos of individual boards. Shipping costs are significant for heavy orders, but online dealers offer access to species and grades not available locally.

Tips for Hand-Selecting Boards

• Look at both faces — flip every board to check both sides before buying. A board that looks perfect on top may have a large check or knot on the back face.
• Check for cup and twist by sighting down the board. A significant cup or twist means more material removed during flattening and planing.
• Look for checks (end-grain cracks) at the ends of boards. These can extend 6–12 inches into a board and must be cut off, reducing usable length.
• Evaluate figure: grain pattern, ray fleck (especially visible in quartersawn oak), and figure intensity vary significantly even within the same species and grade.

Common Mistakes and Pro Tips for Board Foot Calculations

Common Mistakes

• Using actual (dressed) dimensions instead of nominal dimensions in the board foot formula
• Forgetting to include a waste factor — even simple projects lose 10–15% to cutting
• Confusing board feet with linear feet when comparing prices from different suppliers
• Not accounting for surfacing losses when buying rough-sawn lumber
• Ordering the exact calculated quantity with no buffer for defects or damage during delivery
• Ignoring species-specific workability — a wood that costs less per BF may take more time and tooling to process

Pro Tips from Experienced Woodworkers

• Buy boards as long as practical to reduce the number of end joints and minimize end-cut waste
• For figured wood (curly maple, quilted maple), add 20–25% waste — much of the board may not show the figure you want
• Purchase a few extra boards of the most critical pieces (wide panels, long legs) to protect against splitting or tearout
• Check moisture content with a meter before buying — hardwood flooring and furniture wood should be at 6–8% MC
• Ask your dealer for FAS-grade boards if you need long, wide, clear panels — No. 1 Common is better value when smaller, shorter pieces are acceptable
• Compare board foot cost per species: poplar at $5.50/BF may be 40% cheaper than oak for a painted project with no appearance difference

Board Foot Quick Reference Table

Common board footage for frequently used board sizes. These values use the standard nominal dimension formula: BF = (T × W × L) / 12.