Square Ft Calculator

Square Footage Calculator

Total Area: 0 sq. ft.

Total Area (with 10% waste): 0 sq. ft.

Estimated Total Cost: $0.00

function calculateSqFt() { var lFt = parseFloat(document.getElementById('lengthFt').value) || 0; var lIn = parseFloat(document.getElementById('lengthIn').value) || 0; var wFt = parseFloat(document.getElementById('widthFt').value) || 0; var wIn = parseFloat(document.getElementById('widthIn').value) || 0; var price = parseFloat(document.getElementById('pricePerSqFt').value) || 0; var totalLength = lFt + (lIn / 12); var totalWidth = wFt + (wIn / 12); var area = totalLength * totalWidth; var areaWithWaste = area * 1.10; if (area > 0) { document.getElementById('resSqFt').innerText = area.toFixed(2); document.getElementById('resWaste').innerText = areaWithWaste.toFixed(2); if (price > 0) { var totalCost = area * price; document.getElementById('resCost').innerText = totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('costRow').style.display = 'block'; } else { document.getElementById('costRow').style.display = 'none'; } document.getElementById('sqft-results').style.display = 'block'; } else { alert('Please enter valid dimensions.'); } }

Understanding Square Footage Calculations

Whether you are planning a flooring renovation, painting a room, or landscaping your backyard, knowing the exact square footage is the foundation of any successful project. Square footage measures the total area of a surface in two dimensions: length and width.

The Basic Formula for Square Feet

To calculate the square footage of a rectangular or square area, the formula is simple:

Length (ft) × Width (ft) = Total Square Footage (sq. ft.)

Dealing with Inches

In the real world, measurements are rarely perfect whole numbers. If your room is 10 feet 6 inches long, you cannot simply multiply 10.6. You must convert the inches to a decimal fraction of a foot by dividing by 12. For example, 6 inches is 0.5 feet (6/12). Our calculator handles this conversion automatically to ensure your estimates are precise.

Why We Include a 10% Waste Factor

In the results above, you will notice a "10% waste" calculation. In construction and DIY projects, it is industry standard to purchase approximately 10% more material than the net area requires. This account for:

• Cuts and Scraps: Fitting materials into corners or around obstacles.
• Mistakes: Occasional measurement or cutting errors.
• Breakage: Tiles or planks that arrive damaged or break during installation.
• Future Repairs: Having extra matching material for the future.

Practical Example

Imagine you are tiling a kitchen that is 12 feet 3 inches long and 15 feet wide.

1. Convert to decimals: 3 inches / 12 = 0.25 feet. Total length = 12.25 feet.
2. Multiply: 12.25 ft × 15 ft = 183.75 sq. ft.
3. Add Waste: 183.75 × 1.10 = 202.13 sq. ft.

If the tile costs $5.00 per square foot, your estimated material cost would be approximately $918.75.

How to Measure Irregular Rooms

If your room isn't a perfect rectangle (e.g., L-shaped or has alcoves), the best method is "decomposition." Divide the room into smaller rectangles, calculate the square footage of each section individually using the calculator above, and then add the totals together.