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Quickly calculate the board footage of your lumber — no math degree required!
If you've ever tried to estimate lumber for a woodworking project and found yourself lost in the numbers, you're not alone. It's a simple calculation that often confuses the most avid woodworkers when they began their journey making sawdust! That's why we at the Knotty Lumber Co built the board foot calculator. This magical board foot calculator was built for our website to make this crucial step fast, accurate, responsive, and beginner (and professional) friendly. Understanding board footage is essential whether you're a contractor, furniture maker, or just a weekend DIYer. After all, buying too much hardwood lumber eats into your budget, while buying too little stalls your project.
A board foot is simply a unit of measurement accounting for volume. One board foot is equivalent to a piece of wood measuring 12" x 12" x 1" thick.
By contrast, square feet only measure surface area. Two boards can have the same square footage but wildly different board footage if one is thicker. That's why calculating board feet is the smarter method when pricing, planning, or purchasing wood. For example, a 6" wide piece, 10' long may not cost much if its 1" thick, but if its 3” thick it is likely a different story!
Then there's the linear foot, which is simply a measure of length. It doesn't consider width or thickness at all. A 10' board is 10 linear feet—whether it's a skinny trim piece or a wide, thick plank.
Our board foot calculator is a simple tool that does the heavy lifting for you. Whether you're building a table, a stair tread, or a live edge bar top, you can enter your lumber dimensions and get the total board feet instantly. With this board foot calculator, you can even add multiple pieces of lumber to a tally to find out how many board feet are in 1, 10, or 100 pieces!
To use the calculator, all you need are these numbers:
Once entered, the tool will give you the number of board feet.
The board foot calculator automatically adjusts for unit inputs and works seamlessly for multiple boards, helping you plan for larger builds and bulk orders with ease. Its even dynamic so there is no more waiting typing the same thing in hundreds of times with your phone calculator. It has the build in tally so you can add up multiple different sizes.
Different woods may be sold at different thicknesses and widths, especially exotic species like purpleheart or wenge. That's where the board footage calculator becomes essential. For example:
4/4 Lumber (1")
8/4 Lumber (2")
Side by Side
The formula is simple: (Length in inches x Width in inches x Thickness in inches) / 144 = Board Feet
Or in feet: (Length in feet x Width in inches x Thickness in inches) / 12 = Board Feet
One cubic foot contains 12 board feet.
Why? 12" x 12" x 12" = 1728 cubic inches, and one board foot = 12" x 12" x 1" = 144 cubic inches
A linear foot measures only the length. It tells you nothing about the width or thickness. Board footage, however, gives you the full volume, which is critical for lumber pricing and cuts.
Whether you're buying one board foot for a sample or 500 for a commercial project, knowing exactly what you're getting is key. The more accurate your calculations, the less waste, and the more profitable your build. Believe me. It's taken a long time and a lot of poor calculations to learn the hard lessons and the importance of this calculation.
Inaccurate measurements can lead to:
That's why our Board Foot Calculator simplifies everything.
If you're shopping from our online lumber shop, our board foot calculator helps you:
Instead of scribbling math on the back of a receipt, just plug your numbers into our board foot calculator. It's the fastest way to get total board feet with zero guesswork.
From custom charcuterie boards to commercial millwork, we know what goes into a great project. That's why we built a calculator that:
At The Knotty Lumber Co, we're passionate about providing quality wood products and accurate tools. Want to browse by board foot? Our wood products are clearly labeled for easy reference.
When planning your next project, don't leave it to guesswork. Use the board foot calculator to get what you need, when you need it.
Visit our online lumber shop and pick from hundreds of hardwood options today.
A board foot is the standard unit of measurement for lumber. It equals a piece of wood that is 12 inches long, 12 inches wide, and 1 inch thick. The formula is simple: (Thickness" × Width" × Length") ÷ 144. All hardwood lumber — including everything we sell — is priced and sold by the board foot.
Multiply thickness × width × length (all in inches), then divide by 144. For example, a board that is 1" thick, 6" wide, and 48" long works out to 2 board feet (1 × 6 × 48 ÷ 144 = 2). If you have multiple boards, calculate each one and add them together — or use the tally feature in the calculator above to do it automatically.
No project goes perfectly. Offcuts, planning mistakes, grain defects, and saw kerfs all eat into your usable material. A 20% waste buffer is the standard recommendation for most woodworking projects. For highly figured or exotic species where every board counts, some woodworkers go as high as 25–30%. The calculator shows you both the exact board footage and the buffered total so you always order enough.
Once you know your total board footage, multiply it by the price per board foot for your species. For example, if your project needs 15 board feet and your lumber is priced at $9.00/BF, your estimated material cost is $135.00. Enter the price per board foot directly into the calculator and it does this math for you automatically.
4/4 refers to the rough thickness of a board — four quarters of an inch, or 1 inch. In the board foot formula, you use the nominal (rough) thickness, not the finished thickness after surfacing. So a 4/4 board surfaced to 13/16" is still calculated as 1" thick for board footage purposes. This is standard across the hardwood industry.
Yes. Board footage is calculated the same way regardless of species — the formula only uses dimensions, not wood type. The price per board foot will vary by species (Black Walnut costs more per BF than Hard Maple, for example), but the board foot calculation itself is universal. Just enter the price for whatever species you're buying to get an accurate cost estimate.
The Knotty Lumber Co. sells premium kiln-dried hardwood lumber by the board foot, shipped free across Canada and the US. We carry domestic species like Black Walnut, Hard Maple, Cherry, White Oak, and more — as well as exotic hardwoods. Every board is hand-selected by woodworkers, for woodworkers.
