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Calculating Board Feet

How to Calculate Board Feet

Hardwood lumber in the United States and Canada is measured by volume, specifically by the cubic inch.  A board foot of lumber is the volume of one foot in length and one foot wide and one inch thick.  If you measured the volume within that board foot you would fine 144 cubic inches. 

 
OK, that part was for the technical people, now let’s talk English.  To calculate board feet of lumber, multiply thickness by width by length (in inches) and divide by 144 (the number of cubic inches in a board foot).  Actually, you don’t have to convert the length to inches, you can leave it in feet, you would just divide your final number by 12 (inches in a foot) instead of 144.  My advice is to pick one way and always use it.  It can become confusing if you start going from using feet and then back to inches for the measurement of the length.    

Here’s the formula and some examples: 

Thickness x Width x Length (in inches) / 144

If you buy planed wood there are some things to keep in mind.  Board feet will refer to the nominal dimensions of the board (or what the actual dimensions were before any planing was done to the board).  That’s why when you go to buy a 2 x 4 at the home improvement mega store it actually measures 1 ½ x 3 ½.

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