Lumber is often sold in board feet, and board feet do not always correspond with the lineal length of the wood. Specifically, a board that is 1 inch by 12 inches and 1 foot in length is 1 board foot. A 2inch by 12inch board that is 1 foot long would be measured as 2 board feet, while a 1/2inch by 12inch board that is 1 foot in length would be a 1/2 board foot. Being able to convert between board feet and lineal feet is important when buying lumber.
Things You'll Need
 Pencil
 Calculator (optional)
 Measuring tape

Write down the length of your wood in board feet. This will probably be given to you when you buy the wood, but if it is not, you can find out the amount of board feet by dividing the pretax price of the lumber by the cost of the lumber per board foot. Remember that it will sometimes be difficult to know the board feet of the wood you are buying because it does not correspond with lineal feet.

Measure the width and thickness of the board in inches, using a measuring tape. Then multiply the width by the thickness. For example, if the board is 3 inches by 3 inches, you will get 9. If the board is 1 inch by 4 inches, you will get 4.

Divide 12 by the number in Step 2  this will be your multiplier. For example, if the number from Step 2 was 3, the multiplier would be 4. If your number from Step 2 was 18, your multiplier would be 2/3.

Multiply the number of board feet found in Step 1 by the multiplier in Step 3. This will be the length of your board in lineal feet.
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