Free Roofing Square Footage Calculator
Estimate the total square footage of your roof accurately. This is crucial for material ordering and contractor quotes.
Common factors: Flat = 1.0, Low Pitch = 1.1-1.2, Medium Pitch = 1.3-1.4, Steep Pitch = 1.5-1.7. Consult a professional for precise values.
Add 5-15% for cuts, waste, and overlap. 10% is a common starting point.
Estimated Roof Area
— sq ft
Understanding Your Roof's Square Footage
Estimating your roof's square footage is a fundamental step when planning any roofing project, whether it's for repairs, re-shingling, or a complete replacement. Accurate measurements help you get precise quotes from contractors and ensure you order the correct amount of materials, minimizing waste and potential cost overruns. This calculator helps you quickly estimate this crucial number.
How the Calculation Works
The calculation for roof area is based on the roof's dimensions and its pitch (slope).
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Basic Area: For a simple rectangular roof, the area is calculated by multiplying its length by its width.
Basic Area = Roof Length × Roof Width -
Pitch Adjustment: Most roofs are not flat. The pitch, or slope, means the actual surface area of the roof is greater than its footprint on the ground. The 'Pitch Factor' accounts for this. A flat roof has a pitch factor of 1.0. Steeper roofs have higher pitch factors, reflecting the increased surface area. For example, a common moderate pitch might have a factor of around 1.3.
Adjusted Area = Basic Area × Pitch Factor -
Material & Waste Factor: Roofing materials, like shingles or tiles, are not laid perfectly edge-to-edge. There's natural overlap required for weatherproofing, and inevitably, some material is cut and wasted during installation. The 'Material Overlap/Waste Factor' is added as a percentage to the adjusted area to compensate for this. A typical factor is 10%, but this can vary based on the material type and roof complexity.
Total Estimated Area = Adjusted Area × (1 + (Overlap/Waste Factor / 100))
Our calculator simplifies this process by asking for the primary dimensions, a pitch factor, and a waste factor, then providing the total estimated square footage required.
When to Use This Calculator
- Getting Contractor Quotes: Provide your own estimate to compare with quotes from multiple roofing contractors.
- Ordering Materials: Determine the quantity of shingles, underlayment, flashing, and other necessary materials.
- DIY Roofing Projects: Plan your material purchases and budget more effectively.
- Insurance Claims: Understand the scale of roof damage for insurance purposes.
Important Considerations:
While this calculator provides a valuable estimate, always consider:
- Roof Complexity: Dormers, valleys, hips, and skylights add complexity and increase the amount of material and labor needed. This calculator is most accurate for simple gable or hip roofs.
- Material Type: Different roofing materials have varying coverage rates and waste percentages.
- Professional Measurement: For the most accurate final figures, it is always recommended to have a professional roofer measure your roof on-site.