Square Foot Calculator

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square foot calculator
Rectangle / SquareCircleTriangle
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Answer:

Result =

function toggleInputs(){var mode=document.getElementById('given_data').value;var l1=document.getElementById('label1');var l2=document.getElementById('label2');var r2=document.getElementById('row2′);if(mode==='rect'){l1.innerHTML='Length (ft):';l2.innerHTML='Width (ft):';r2.style.display='table-row';}else if(mode==='circle'){l1.innerHTML='Radius (ft):';r2.style.display='none';}else if(mode==='triangle'){l1.innerHTML='Base (ft):';l2.innerHTML='Height (ft):';r2.style.display='table-row';}}function calculateResult(){var mode=document.getElementById('given_data').value;var v1=parseFloat(document.getElementById('input1').value);var v2=parseFloat(document.getElementById('input2').value);var p=parseFloat(document.getElementById('input3').value);var showSteps=document.getElementById('steps').checked;var area=0;var details=";if(isNaN(v1)){alert('Please enter a valid primary measurement');return;}if(mode==='rect'){if(isNaN(v2)){alert('Please enter width');return;}area=v1*v2;details='Area = Length × Width = '+v1+' × '+v2+' = '+area.toFixed(2)+' sq ft';}else if(mode==='circle'){area=Math.PI*Math.pow(v1,2);details='Area = π × r² = 3.14159 × '+v1+'² = '+area.toFixed(2)+' sq ft';}else if(mode==='triangle'){if(isNaN(v2)){alert('Please enter height');return;}area=0.5*v1*v2;details='Area = ½ × Base × Height = 0.5 × '+v1+' × '+v2+' = '+area.toFixed(2)+' sq ft';}var output='
'+area.toFixed(2)+' Square Feet
';if(showSteps){output+='
'+details+'
';}if(!isNaN(p)){var totalCost=area*p;output+='
Total Cost: $'+totalCost.toLocaleString(undefined,{minimumFractionDigits:2,maximumFractionDigits:2})+'
';}document.getElementById('answer').innerHTML=output;}

Calculator Use

The square foot calculator is an essential tool for homeowners, contractors, and DIY enthusiasts looking to determine the area of a surface in square feet. Whether you are ordering flooring, planning a garden, or calculating the paint needed for a room, knowing the exact square footage ensures you buy the correct amount of materials and stay within budget.

By entering simple dimensions like length, width, or radius, this calculator provides instant results. You can also input a price per square foot to estimate the total cost of your project.

Length / Base / Radius
The primary horizontal measurement of your shape. For rectangles, it is the length; for triangles, the base; and for circles, the distance from the center to the edge.
Width / Height
The secondary vertical measurement. This is required for rectangular and triangular shapes to determine the total surface area.
Price per Square Foot
An optional field used to calculate the financial cost of the materials required for the specified area.

How It Works

The calculation of square footage depends entirely on the geometry of the space. The square foot calculator utilizes standard geometric formulas to derive the area based on your inputs.

Area (Rectangle) = Length × Width
Area (Circle) = π × Radius²
Area (Triangle) = ½ × Base × Height

  • Rectangles: The most common room shape. Multiply the two perpendicular sides.
  • Circles: Used for circular patios or fire pit areas. The radius is squared and multiplied by Pi (~3.14159).
  • Triangles: Useful for calculating gables or corner lots. Multiply the base by the height and divide by two.
  • Costing: Once the area is found, multiplying by the unit price gives the total estimated expense.

Calculation Example

Example: Suppose you are installing hardwood flooring in a living room that measures 20 feet long and 15 feet wide. The flooring costs $8.50 per square foot.

Step-by-step solution:

  1. Identify dimensions: Length = 20 ft, Width = 15 ft.
  2. Choose formula: Area = Length × Width.
  3. Calculate Area: 20 × 15 = 300 sq ft.
  4. Calculate Cost: 300 sq ft × $8.50 = $2,550.00.
  5. Result: You need 300 square feet of material, costing approximately $2,550.

Common Questions

How do I calculate square feet if my measurements are in inches?

If you measure in inches, first convert the dimensions to feet by dividing by 12. For example, 18 inches is 1.5 feet (18 / 12 = 1.5). Alternatively, multiply the inches (e.g., 120 in x 144 in = 17,280 sq in) and divide the final result by 144 to get square feet (17,280 / 144 = 120 sq ft).

Should I buy extra material for waste?

Yes. Most professionals recommend adding a 10% "waste factor" to your total square footage to account for cuts, mistakes, and broken pieces. For the example above (300 sq ft), you would order 330 square feet.

Can I use this for walls?

Absolutely. To calculate the square footage of a wall, treat the wall's width as the "Length" and the wall's height as the "Width" in the calculator. Subtract the square footage of windows and doors for a more accurate paint or wallpaper estimate.

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