Board Foot Calculator

A board foot calculator is used to calculate the volume of lumber by the dimensions of the lumber. It helps determine the amount of wood in board feet, a standard unit of measurement in the lumber industry. The board foot is defined as a piece of lumber that measures 12 inches by 12 inches by 1 inch, or 144 cubic inches. The purpose of the Board Foot Calculator is to help professionals and Dryers more easily estimate how much wood will be needed for furniture building, construction, or woodworking projects. For precision in your project planning, getting timber volume takeoff can help refine your wood requirements, ensuring efficiency and cost-effectiveness. 

With the input of length, width, and thickness of a piece of lumber, the calculator returns the total board feet, thus aiding in the estimations of cost, ordering material, and preventing wastage. This tool allows for accurate measurements with an eye toward budget and efficient planning in any project that involves wood. 

Calculation Process

A board foot measures standard lumber sizes; it computes all the attributes-thickness, width, and length of a particular piece of wood. Ensuring accurate measurement and calculation would apply whether the project is one on which a professional or amateurish do-it-yourselfer may undertake. The following provides detailed, step-by-step how-to in board-foot calculation that shows formulas, examples, and other applicable tips to any project you need to take for real action.

Formula of Calculating Board Foot

The number of board feet can be computed with the help of the formula

Board Feet (BF)=Thickness (in inches) x width (in inches) x Length (in feet)12

This formula multiplies the three dimensions thickness, width, and length and divides by 12. This is necessary because there are 12 inches in a foot, and it converts the cubic inches into board feet. The volume of the lumber will be provided to you as board feet in the result. Board feet are a common unit for measuring lumber within the industry.

Step 1: Measure Dimensions

The first step in the process is gathering accurate measurements of the board. You’ll need to measure three primary dimensions:

Thickness: This is typically the smallest dimension and is measured in inches. For example, 1 inch, 2 inches, or any other thickness.

Width: The width is measured across the broad face of the board, usually in inches.

Length: This is how long the board is, end to end, measured in feet. If you were given the measurement in inches, just divide that number by 12 to get your answer in feet.

Example 1: Measure

You are given a board with the following measures

Thickness: = 2 inches

Width: = 6 inches

Length: = 10 feet

These are your measurements for this step of the process.

Step 2: Use the Formula

Now that you have your measurements, you can use the formula to determine the number of board feet.

Formula 

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

Example: Single Board Calculation

Applying the values from

 Example 1

• Thickness: = 2 inches
• Width: = 6 inches
• Length: = 10 feet

Substitute These Values in The Formula

• Board Feet:=2×6×10/ 12
• Multiply the thickness and the width: 2×6=122
• Multiply the result by the length: 12×10=120
• Finally, divide by 12 to express the result in board feet: 120 / 12=10 Board
• Result: The board has 10 board feet.

Step 3: Calculation for Several Boards

When calculating board feet for several boards, you merely multiply the board feet for a single board by the number of boards.

Example: Calculation for Several Boards

Assume you have 15 boards, and their dimensions are as follows:

• Thickness: = 1.5 inches
• Width: = 4 inches
• Length: = 8 feet
• Step 1: Calculate board feet for a single board.
• Board Feet: =1.5×4×812=4 Board Feet per board

 Multiply by the number of boards.

• Total Board Feet: =4×15=60 Board Feet
• Result: The total board feet for 15 boards is 60 board feet.

Step 4: Adjust for Waste

It is always a good rule of thumb to add some waste or loss when cutting and working with lumber. Waste can occur due to defects, trimming, and planning. A good rule of thumb is to add 5–10% to your total.

Example: Adding Waste

• Assume the total board feet needed for your project is 100. If you choose to add 10% for waste:
• Step 1: Calculate the waste.
• Waste: =100×0.10=10 Board Feet
• Step 2: Add the waste to the total board feet.
• Total Board Feet (with waste)=100+10=110 Board Feet
• Conclusion: Order 110 board feet of lumber to account for waste.
• Step 2: Add the waste to the total board feet.

• Total Board Feet (with waste)=100+10=110 Board Feet
• Here, you would want to order 110 board feet for both your project and your waist.

Step 5: Using Length in Inches

If your board lengths are measured in inches, not feet, you will use a slightly different formula. To convert to board feet when measured in inches, divide by 144 (because 12 inches × 12 inches = 144 cubic inches in a board foot) rather than 12.

Example: Length in Inches

• Assume that you have the following board dimensions:
• Thickness: = 1 inch
• Width: = 8 inches
• Length: = 72 inches (which is 6 feet)
• Step 1: Use the formula with inches for length.
• Board Feet (BF)=1×8×72 / 144=4 Board Feet
• So, the board has 4 board feet if measured in inches.

Step 6: Dealing with Irregular Boards

For irregular boards that do not have uniform measurements, you may use the average thickness, width, and length. This approach helps you come up with an approximate total of board feet from the lumber.

Example

• Assume that you have an irregular board that has an average thickness of 1.25 inches, an average width of 7 inches, and a length of 72 inches.

Use the Formula with Average Dimensions.

• Board Feet (BF)=1.25×7×72 /12=4.375 Board Feet In the above example, the irregular board has about 4.375 board feet.

Total Board Feet for More than One Piece

• In multi-piece projects, you will be looking to calculate more than one board’s board foot. After the calculation of individual board feet from each piece, add them up because the total boards have been added.

Sum of Several Boards

• Let’s say you have two types of boards with the following dimensions:
• Board 1: 2 inches × 6 inches × 10 feet
• Board 2: 1.5 inches × 4 inches × 8 feet

Calculate Board Feet for Board 1.

• Board Feet(BF):=2×6×1012=10 Board Feet

Step 2: Calculate Board Feet for Board 2.

• Board Feet(BF):=1.5×4×8 / 12=4 Board Feet
• Total Board Feet:=10+4=14 Board Feet
• For both boards, the total needed lumber is 14 board feet.

Step 8: Calculate for a Long Piece of Lumber

As soon as you have established board feet per lineal foot, you can determine how many board feet are in any length of lumber. To find this, simply multiply the board feet per lineal foot by the total number of lineal feet in the lumber.

Example: Calculation for a Longer Piece of Lumber

Suppose you have a 12-foot-long lumber piece with 2 inches of thickness and 6 inches of width.

From the previous computation, we found that there is 1 board foot per linear foot.

Now multiply by the total number of linear feet:

Total Board Feet=1×12=12 Board Feet

Thus, a 12-foot lumber piece with 2 inches of thickness and 6 inches of width contains 12 board feet.

Step 9: Total Board Feet for Complex Projects

For complex woodworking projects that involve multiple boards of various sizes, you’ll need to calculate the board feet for each piece and then add them up.

Example: Total Board Feet for Multiple Sizes

Suppose you have two types of boards with the following dimensions:

• Board 1: 2 inches × 6 inches × 10 feet
• Board 2: 1.5 inches × 4 inches × 8 feet
• Step 1: Calculate board feet for Board 1.
• Board Feet=2×6×1012=10 Board Feet

Calculate Board Feet for Board 2

• Board Feet=1.5×4×812=4 Board Feet

 Add the Board Feet Together

• Total Board Feet:=10+4=14 Board Feet
• Result: The total board feet for both boards is 14 board feet.

Lumber Size and Their Board Feet per Liner Foot 

This table provides an overview of lumber sizes and their board feet per lineal foot. 

Lumber Size	Board Feet per Linear Foot
1×4	0.0333
1×6	0.05
2×4	0.0833
2×6	0.125
2×8	0.1667
4×4	0.3333
4×6	0.5