Board Feet Calculator

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Board Feet Calculator
Thickness(in) x Width(in) x Length(ft)Thickness(in) x Width(in) x Length(in)
Results:
function calculateBF(){var t=parseFloat(document.getElementById('thickness').value);var w=parseFloat(document.getElementById('width').value);var l=parseFloat(document.getElementById('length').value);var q=parseFloat(document.getElementById('quantity').value);var p=parseFloat(document.getElementById('price').value);var type=document.getElementById('calc_type').value;var showSteps=document.getElementById('showSteps').checked;if(isNaN(t)||isNaN(w)||isNaN(l)||isNaN(q)){alert('Please enter valid dimensions and quantity.');return;}var bfPerPiece=0;var divisor=12;var unitLabel="ft";if(type==="inches"){bfPerPiece=(t*w*l)/144;divisor=144;unitLabel="in";}else{bfPerPiece=(t*w*l)/12;}var totalBF=bfPerPiece*q;var resultHTML="Total Board Feet: "+totalBF.toFixed(2)+" bd ft";if(!isNaN(p)&&p>0){var totalCost=totalBF*p;resultHTML+="
Total Cost: $"+totalCost.toFixed(2)+"";}document.getElementById('resultOutput').innerHTML=resultHTML;if(showSteps){var stepText="Step-by-Step Calculation:
";if(type==="feet"){stepText+="Formula: (Thickness\" × Width\" × Length') / 12 × Quantity
";stepText+="Calculation: ("+t+" × "+w+" × "+l+") / 12 × "+q+" = "+totalBF.toFixed(2)+" bd ft";}else{stepText+="Formula: (Thickness\" × Width\" × Length\") / 144 × Quantity
";stepText+="Calculation: ("+t+" × "+w+" × "+l+") / 144 × "+q+" = "+totalBF.toFixed(2)+" bd ft";}document.getElementById('stepsOutput').innerHTML=stepText;document.getElementById('stepsOutput').style.display='block';}else{document.getElementById('stepsOutput').style.display='none';}document.getElementById('answer').style.display='block';}

How to Use the Board Feet Calculator

A board feet calculator is an essential tool for woodworkers, carpenters, and lumber yards to accurately measure wood volume. Unlike square footage or linear footage, board feet measure the actual volume of wood in a piece of lumber. This calculator allows you to quickly determine the volume of multiple boards and estimate the total cost based on the price per board foot.

To use this calculator, simply enter the dimensions of your lumber and the quantity of pieces you have. You can also include the price per board foot provided by your supplier to get an instant cost estimate.

Thickness (inches)
The thickness of the board measured in inches. Note that hardwood is often sold in "quarters" (e.g., 4/4 is 1 inch thick).
Width (inches)
The width of the board measured across the grain in inches.
Length (feet or inches)
The total length of the board. You can choose to enter this in feet (standard) or inches using the dropdown menu.
Price per Board Foot
The cost assigned by the lumber yard for one board foot of that specific species and grade of wood.

How It Works

One board foot (bd ft) is defined as a volume equivalent to a square board that is 12 inches wide, 12 inches long, and 1 inch thick. This equals 144 cubic inches. The formula used depends on whether your length is measured in feet or inches:

Board Feet = (Thickness" × Width" × Length') / 12

If all dimensions are in inches, use this formula:

Board Feet = (Thickness" × Width" × Length") / 144

  • Thickness: Always use the nominal thickness unless you are measuring rough-cut lumber where you use the actual dimension.
  • Width: Measured in inches.
  • Length: Standard lumber is usually measured in feet.
  • Quantity: Multiply the result by the number of identical pieces to find the total volume.

Calculation Example

Example: You are buying five 2×6 boards that are each 10 feet long. The price for this cedar is $4.50 per board foot.

Step-by-step solution:

  1. Thickness = 2 inches
  2. Width = 6 inches
  3. Length = 10 feet
  4. Quantity = 5 pieces
  5. Calculate per board: (2 × 6 × 10) / 12 = 10 bd ft per piece
  6. Total Board Feet: 10 × 5 = 50 bd ft
  7. Total Cost: 50 × $4.50 = $225.00

Common Questions

What is the difference between board feet and linear feet?

Linear feet only measures the length of the board regardless of its width or thickness. Board feet measures total volume. For example, a 10-foot long 2×4 and a 10-foot long 2×8 both have 10 linear feet, but the 2×8 has twice the board feet because it is twice as wide.

Do I use nominal or actual dimensions?

In the lumber industry, board feet are typically calculated using nominal dimensions (the size before the board was surfaced/planed). However, for rough-cut lumber or custom woodworking, you use the actual dimensions. If you are buying a "2×4″ from a big-box store, it is actually 1.5″ x 3.5", but it is charged based on the 2×4 nominal size.

How do I calculate board feet for 4/4, 5/4, or 8/4 lumber?

Hardwood is often sold by "quarters" of an inch. 4/4 (four-quarter) is 1 inch thick, 5/4 is 1.25 inches thick, and 8/4 is 2 inches thick. When using the board feet calculator, simply enter the decimal equivalent (1, 1.25, or 2) into the thickness field.

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