Converting Cubic Meters to Board Feet

The math isn't hard, but there are a few fine points. June 12, 2014

Question
I'm looking into having some teak shipped from China. They quote me a quantity of m2 or m3. Does someone know what that equals in board feet?

Forum Responses
(Commercial Kiln Drying Forum)
From contributor M:
I am guessing that...
m2 equals square meters or length in meters times width in meters.
m3 equals cubic meters or length in meters times width in meters times thickness in meters.

Also, m3 or cubic meters can be substituted for board foot. I am sure you know that a board foot is the length in inches times the width in inches times the thickness in inches; then you take the product and divide by 144 to get board feet units. The point here is a board foot is a unit of measure that is a cubic unit; this case cubic inches.

The rest of the world measures wood products in m3, we Americans use board feet. It's that whole metric thing that brought us the liter bottle of Coke. I hope this did not confuse you further.

From contributor I:
The cubic M is a simple measure - it's a lump of wood 1 meter cube. That's about 39 inches. The exact conversion is a bit confused because the board foot measure is a bit variable, but it's something around 425 bdft to a cubic m. Anyone else, feel free to check my maths. It's late at night here in NZ.

From contributor D:
425BF/M3 is very close. Flooring is usually sold in square meters (M2) and that is about 10 square feet.

From contributor R:
If you haven't invested in a calculator from the Construction Master people yet, I strongly suggest you do. These calculators will do the conversions for you from board feet to metric at the push of a button. They're about \$100.00 and worth every penny! I own a desktop model called PRO-DT and a palm size model I keep in the shop called Construction Master IV. Also great tools to have for trig and geometry functions, roof pitches, stairs, rise/run calcs, etc.

From Professor Gene Wengert, forum technical advisor:
Please check the archives here for some interesting insight into the board feet and cubic meter conversion.

For example, hardwood lumber board foot is often 1.125" x 12" x 12" and not 1.0" x 12" x 12". So, how is that adjusted when figuring cubic meters? For softwoods, the actual size is 1.5 x 3.5 8' for a 2x4 that has 5.33 BF. How is that converted to cubic meters... Do you use the actual or the nominal size?

From contributor W:
NHLA rulebook states that there are 424 board feet per M3 (CBM).
The math: 1 meter = 39.3701"
39.3701 * 39.3701 *39.3701 = 61023.84295 cubic inches per M3
1" x 12" x 12" = 144"/BF
61023.84295/144 = 423.7766872 BF/M3
Amazingly the NHLA is correct.

From Professor Gene Wengert, forum technical advisor:
As contributor D points out, the conversion of BF to metric is straightforward, but it is important to understand that the nominal size is used (1" thickness is the above calculation) and not the actual size, which is often 1-1/8". Likewise, any piece of 12' long lumber would be 12 BF if it is 11.5" to 12.5" wide.