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How Is Hardwood Lumber Measured?

Hardwood lumber volume is measured and priced by board feet and labeled using the quarter system.  One board foot is equivalent to a board that is one foot long by one foot wide by one inch thick.  If a board were 2 inches thick by 8 feet long by 1 foot wide, it would be equivalent to 16 board feet since the thickness plays a role in the calculation.

Board feet is commonly abbreviated as BF, FBM, or MBF.

How To Calculate Board Feet

Sawmills and buyers of lumber often use board feet as a unit of measurement.  Below is the formula to calculate how many board feet a piece of lumber is.

Width (in) x Thickness (in) x Length (in) / 144 = Board Feet


Width (in) x Thickness (in) x Length (ft) / 12 = Board Feet


This formula can also be used to calculate multiple boards at once.  It's safe to say that most customers at a sawmill don't just purchase one piece of lumber.  If a customer is buying in bulk for a particular board type, you can calculate it with the formula below:

Pieces x Width (in) x Thickness (in) x Length (ft) / 12 = Board Feet

When calculating board feet, if the numbers seem high then check your formula to ensure you used the correct measurements (feet or inches) for each dimension. Then ensure you divided by 12 or 144. You divide by 144 when all of the dimensions are in inches.

The Quarter System: The Lumber Says 5/4. What does that Mean?

The quarter system is used for measuring rough cut lumber.  It simply refers to how many 1/4 inches the rough wood stock equals.  To put it simply, rough cut lumber is labeled as:

  • 5/4 stock = lumber that is 1 1/4" wide
  • 6/4 stock - lumber that that is 1 1/2" wide
  • 7/4 stock - lumber that is 1 3/4" wide
  • 8/4 stock - lumber that is 2" wide
  • 10/4 stock - lumber that is 2 1/2" wide

You get the point - every 1/4 is just a quarter inch.

Please keep in mind that the quarter system is only used for roughsawn lumber. Finished lumber, like you might buy at a big box hardware store, is usually finished.  That's why why you buy a 2x4, it's really only 1.5" x 3.5".  This is because the board is finished.  During the finishing process, lumber is dried and planed, which reduces it a half inch. If you need an actual 2" thick piece of lumber, you'll likely need to buy it rough sawn.

Ready To Buy Hardwood Lumber? Contact Us Today.

Beiler's sawmill is a leading supplier of domestic hardwood lumber to those in the Lancaster, PA area and beyond.  Review our website and fill out our contact form if you have a need for roughsawn lumber!