.bf-calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
color: #333;
line-height: 1.6;
}
.bf-calc-box {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 30px;
margin-bottom: 40px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.bf-calc-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 24px;
font-weight: 700;
}
.bf-input-group {
margin-bottom: 20px;
}
.bf-input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #495057;
}
.bf-input-row {
display: flex;
gap: 15px;
flex-wrap: wrap;
}
.bf-col {
flex: 1;
min-width: 200px;
}
.bf-input-wrapper {
position: relative;
display: flex;
}
.bf-input-wrapper input, .bf-input-wrapper select {
width: 100%;
padding: 12px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
}
.bf-input-wrapper select {
width: 30%;
margin-left: -1px;
border-top-left-radius: 0;
border-bottom-left-radius: 0;
background-color: #e9ecef;
}
.bf-input-wrapper input.has-append {
border-top-right-radius: 0;
border-bottom-right-radius: 0;
}
.bf-btn {
width: 100%;
background-color: #8B4513;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.2s;
margin-top: 10px;
}
.bf-btn:hover {
background-color: #6d360f;
}
.bf-results {
margin-top: 25px;
padding: 20px;
background-color: #fff;
border: 1px solid #dee2e6;
border-radius: 4px;
display: none;
}
.bf-result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.bf-result-row:last-child {
border-bottom: none;
}
.bf-result-label {
font-weight: 600;
color: #555;
}
.bf-result-value {
font-weight: 700;
color: #2c3e50;
font-size: 18px;
}
.bf-article h2 {
color: #2c3e50;
border-bottom: 2px solid #8B4513;
padding-bottom: 10px;
margin-top: 40px;
}
.bf-article h3 {
color: #5d4037;
margin-top: 25px;
}
.bf-article ul {
padding-left: 20px;
}
.bf-article li {
margin-bottom: 10px;
}
.bf-error {
color: #dc3545;
font-size: 14px;
margin-top: 5px;
display: none;
}
function calculateBoardFeet() {
var pieces = parseFloat(document.getElementById('bf-pieces').value);
var thick = parseFloat(document.getElementById('bf-thick').value);
var width = parseFloat(document.getElementById('bf-width').value);
var length = parseFloat(document.getElementById('bf-length').value);
var lenUnit = document.getElementById('bf-len-unit').value;
var price = parseFloat(document.getElementById('bf-price').value);
var errorMsg = document.getElementById('bf-error-msg');
var resultBox = document.getElementById('bf-result-box');
var costRow = document.getElementById('bf-cost-row');
// Validation
if (isNaN(pieces) || pieces < 1) pieces = 1;
if (isNaN(thick) || isNaN(width) || isNaN(length) || thick <= 0 || width <= 0 || length 0) {
var totalCost = totalBF * price;
document.getElementById('bf-res-cost').innerText = '$' + totalCost.toFixed(2);
costRow.style.display = 'flex';
} else {
costRow.style.display = 'none';
}
resultBox.style.display = 'block';
}
What is a Board Foot?
A Board Foot (often abbreviated as FBM, meaning "Foot Board Measure") is a specialized unit of volume used exclusively in the lumber industry of the United States and Canada. Unlike square footage, which only measures surface area, board footage measures the total volume of wood.
One board foot is defined as a piece of wood that is 12 inches long, 12 inches wide, and 1 inch thick. This equates to 144 cubic inches of lumber.
Why Use the Omni Board Foot Calculator?
Lumberyards and sawmills typically sell hardwood (like oak, maple, walnut, or cherry) by the board foot rather than by the linear foot or per piece. This is because hardwood trees vary wildly in size, and rough lumber is sold in random widths and lengths. This calculator allows woodworkers, contractors, and DIY enthusiasts to:
- Accurately estimate the volume of lumber needed for a project.
- Convert linear dimensions (Thickness, Width, Length) into Board Feet (BF).
- Calculate the total cost of materials based on the price per BF.
Board Foot Formula
The math behind calculating board feet is straightforward. It is essentially a volume calculation normalized to a 1-inch thickness. There are two common variations of the formula depending on how you measure the length of the board.
1. If Length is in Feet (Most Common)
If you measure the length of the board in feet, but the thickness and width in inches, use this formula:
BF = (Thickness × Width × Length) ÷ 12
Example: A 2″ thick × 6″ wide × 8′ long board:
(2 × 6 × 8) ÷ 12 = 96 ÷ 12 = 8 Board Feet.
2. If Length is in Inches
If you measure all dimensions (Thickness, Width, and Length) in inches, use this formula:
BF = (Thickness × Width × Length) ÷ 144
Example: A 1″ thick × 12″ wide × 12″ long board:
(1 × 12 × 12) ÷ 144 = 144 ÷ 144 = 1 Board Foot.
Nominal vs. Actual Dimensions
When buying softwood construction lumber (like 2x4s), you usually pay per piece. However, when calculating board feet for rough-sawn hardwood, calculations are generally based on the nominal size (the size of the wood before it was dried and planed).
For example, if you buy "4/4" lumber (nominal 1 inch thick), it may be surfaced down to 3/4 inch thick, but you are still charged for the full 1-inch nominal thickness. Always enter the nominal thickness into the Omni Board Foot Calculator to ensure your cost estimates match the lumberyard's invoice.
Common Thicknesses (Quarters system)
- 4/4 = 1 inch nominal
- 5/4 = 1.25 inches nominal
- 6/4 = 1.5 inches nominal
- 8/4 = 2 inches nominal
Calculating Project Cost
To determine the total cost of your lumber purchase, simply multiply the total Board Feet by the price per Board Foot. Our calculator handles this automatically if you input the price.
Example Cost Calculation:
You need 5 boards of Walnut. Each board is 1″ thick, 8″ wide, and 10′ long.
1. Calculate BF per board: (1 × 8 × 10) ÷ 12 = 6.67 BF.
2. Total BF: 6.67 BF × 5 pieces = 33.35 BF.
3. If Walnut is $12.00/BF: 33.35 × $12.00 = $400.20 Total Cost.