What is the difference between board foot, lineal foot, and square foot?
Posted: September 15, 2025Author – Ryan Palma Owner/CEO Sustainable Lumber Co.
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What is the difference between board foot, lineal foot, and square foot?
Understanding Lumber Measurements: Board Foot vs. Lineal Foot vs. Square Foot
If you’ve ever stared at a lumber yard receipt or tried to calculate how much material you need for your next project, you’ve probably encountered some confusing terms like “board foot,” “lineal foot,” and “square foot.” These aren’t just random jargon, they’re essential units of measurement in the lumber world that help you buy the right amount of wood without overpaying or coming up short. In this post, we’ll break them down step by step, explain their differences, and even throw in a handy comparison table. Whether you’re building a deck, installing a floor, or just curious; here’s the breakdown.
What is a Board Foot?
First up, the board foot. This is one of the most common measurements in the lumber industry, especially for rough-sawn or dimensional lumber. A board foot isn’t about length or area, it’s a unit of volume. Specifically, it represents the volume of a piece of wood that’s 1 inch thick, 12 inches wide, and 12 inches long, which equals 144 cubic inches.
Why does this matter? Well, lumber is often priced and sold by board feet because it accounts for all three dimensions: thickness, width, and length. This is super useful when you’re dealing with irregular or varying sizes of wood.
The formula to calculate board feet is straightforward: (Thickness in inches × Width in inches × Length in feet) ÷ 12
For example, take a classic 2×4 board that’s 8 feet long. Plugging in the numbers: (2 × 4 × 8) ÷ 12 = 5.33 board feet. Boom, now you know exactly how much wood you’re getting! This measurement is often used in scenarios like woodworking shops or when milling logs into usable lumber.
What is a Lineal Foot (or Linear Foot)?
Next, let’s talk about the lineal foot, sometimes called a linear foot. This one’s simpler: it only measures length. One lineal foot equals 12 inches of straight-line distance, completely ignoring the width and thickness of the wood.
You’ll see lineal feet used for items where the cross-section is standard or doesn’t affect pricing, like trim molding, baseboards, fencing rails, porch decking, or even pipes. It’s all about how much linear coverage you need, not the bulk.
Picture this: If you’re installing crown molding around a room and the supplier quotes “10 lineal feet,” that means you’re getting 10 feet of length, no matter if it’s 3 inches wide or 6 inches thick. Just measure the total run of your project and multiply by the price per lineal foot.
What is a Square Foot?
Last but not least, the square foot. This is a unit of area, focusing on the surface coverage rather than volume or length. It’s calculated as length in feet × width in feet (or simply 144 square inches for one square foot). Thickness? That’s usually specified separately and doesn’t factor into the square footage.
Square feet are your go-to for sheet goods or flat materials, such as plywood, OSB panels, flooring, or siding. These are all about how much ground (or wall) they’ll cover.
A real-world example: A standard 4×8 sheet of plywood? That’s 4 feet by 8 feet, covering a whopping 32 square feet. Perfect for estimating how many sheets you need for a subfloor or roof sheathing. Just remember, if thickness matters for your project (like in structural applications), you’ll note that on the side.
Key Differences at a Glance
To make it even easier, here’s a quick comparison table summarizing the big differences:
| Measurement | Dimension Type | Used For | Calculation Example |
| Board Foot | Volume (3D) | Measuring lumber volume (e.g., hardwoods, rough lumber) | 1″ × 12″ × 12″ = 1 board foot |
| Lineal Foot | Length (1D) | Measuring length only (e.g., trim, rails) | 12″ length = 1 lineal foot (width/thickness ignored) |
| Square Foot | Area (2D) | Measuring surface coverage (e.g., sheets, flooring) | 12″ × 12″ = 1 square foot (thickness separate) |
As you can see, each unit serves a unique purpose based on what aspect of the wood you’re focusing on. Mixing them up could lead to costly mistakes, like buying too much trim or not enough plywood!
Wrapping It Up: Choose the Right Measurement for Your Project
There you have it, a clear guide to navigating board feet, lineal feet, and square feet in the world of lumber. Next time you’re at the hardware store or planning a build, you’ll be armed with the knowledge to speak the lingo and get exactly what you need. Pro tip: Always double-check your calculations and ask the supplier if you’re unsure, they’re usually happy to help!
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