What Is a Board Foot? (And Why Does it Matter?)

on June 20, 2025


To all the woodworkers, DIY-ers, and soon-to-be lumber buyers out there…

If you’ve ever stared at the price tag on wood wondering why it’s priced per board foot instead of like a regular product, you’re not alone.

Board footage confuses everyone at first. The worst part? If something is priced at $10 per board foot, we both found out really quickly that hardwood isn’t sold for ten bucks a stick.

That being said, once you get the hang of the math, it’s like unlocking the cheat code to shopping for wood the smart way.

🧱 What Is a Board Foot? (and Why Does It Matter?)

Let’s break it down.

A board foot is a unit of measurement commonly used in the lumber industry for volume. It’s not weight. Not area. Volume.

Think of a board foot as one square foot of wood that is one inch thick.

In other words:
1 board foot = 12 inches × 12 inches × 1 inch = 144 cubic inches

Why is it used? Because lumber doesn’t come in tidy little boxes. It comes in random lengths, widths, and thicknesses, so we need a consistent way to measure and price the volume of wood you’re actually buying.

🧐 Why Do Board Feet Matter?

If you’re buying rough lumber, dressed boards, or ordering a custom cut, your cost is usually calculated by the board foot. Knowing how to calculate it yourself means:

  • You’ll spot a great deal (or a ripoff) a mile away
  • You can budget accurately for your next project
  • You won’t get that “am I being overcharged” feeling

And if you're shopping with us at The Knotty Lumber Co., we make it easy, but it’s still good to know what you’re looking at.

🧮 How Do I Calculate Board Feet?

Here’s the formula:

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

Or:

Board Feet = (Length in inches × Width in inches × Thickness in inches) ÷ 144

Or just use our calculator. But if you’re a pen-and-paper kind of person, here’s an example.

✏️ Example:

Let’s say you want 15 boards. Each board is:

  • 8 feet long
  • 10 inches wide
  • 1.25 inches thick

Board feet per board:

8 × 10 × 1.25 ÷ 12 = 8.33 board feet

Total board feet:

15 × 8.33 = 125 board feet

If your wood costs $7.50 per board foot:

125 × $7.50 = $937.50

Boom. Just like that, you’re ahead of the game next time you hit the lumber yard.

💡 Final Thoughts

Understanding board feet is the first step to buying smart and budgeting better. The best part? It helped me sound like I knew what I was doing the first time I walked into a lumber yard.

And hey, even if you forget the formula, we’ve got a calculator ready for you at The Knotty Lumber Co.

Keep stacking those board feet, and remember: when in doubt, buy a little extra. It’s better than coming up short mid glue up.

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