Lf to Sf Calculator

Linear Feet to Square Feet Calculator

Inches Feet

Total Area: 0 Square Feet (SF)

function calculateSF() { var lf = parseFloat(document.getElementById("linearFeet").value); var width = parseFloat(document.getElementById("materialWidth").value); var unit = document.getElementById("widthUnit").value; var resultDiv = document.getElementById("resultArea"); var display = document.getElementById("sfResult"); if (isNaN(lf) || isNaN(width) || lf <= 0 || width <= 0) { alert("Please enter valid positive numbers for both Linear Feet and Width."); return; } var sf; if (unit === "inches") { // Convert inches to feet by dividing by 12 sf = lf * (width / 12); } else { // Width is already in feet sf = lf * width; } display.innerHTML = sf.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); resultDiv.style.display = "block"; }

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Understanding Linear Feet vs. Square Feet

When planning a construction, flooring, or decking project, understanding the difference between Linear Feet (LF) and Square Feet (SF) is crucial for accurate material ordering. While they sound similar, they measure very different dimensions.

• Linear Feet (LF): A measure of length only. It does not account for the width or thickness of the material.
• Square Feet (SF): A measure of total surface area (Length × Width).

How to Convert LF to SF

To convert linear feet to square feet, you must know the width of the material you are using. The formula is straightforward:

Square Feet = Linear Feet × (Width of board in inches ÷ 12)

Example Calculation:

Imagine you are buying 200 linear feet of 6-inch wide cedar decking boards. To find out how many square feet this covers:

1. Convert the width to feet: 6 inches ÷ 12 = 0.5 feet.
2. Multiply by the length: 200 LF × 0.5 feet = 100 Square Feet.

Common Material Widths

Nominal Size	Actual Width	Conversion Factor (SF per LF)
1×4 Board	3.5 inches	0.291 SF
1×6 Board	5.5 inches	0.458 SF
1×8 Board	7.25 inches	0.604 SF

Why Use This Calculator?

Contractors and DIYers use this calculator to estimate coverage for siding, decking, fencing, and hardwood flooring. Because these materials are often sold by the linear foot but installed to cover a square foot area, getting this conversion right prevents overspending or running out of materials mid-project. Always remember to add a 10% waste factor to your final square footage result for cuts and mistakes!