Estimate the amount of roofing materials needed for your project, including shingles, underlayment, flashing, and fasteners. Get accurate quantities to help plan your roofing project and budget with confidence.
Calculating the right amount of roofing materials is crucial for accurate budgeting and smooth project execution. This guide will help you understand roofing measurements, materials, and important considerations for your roofing project.
Roofing materials are typically sold in "squares," where one square equals 100 square feet of roof coverage.
A common mistake is assuming the roof area equals the house's footprint area. In reality, the roof area is larger due to:
Roof pitch is expressed as the ratio of vertical rise to horizontal run, typically as X/12, where X is the number of inches of vertical rise for every 12 inches of horizontal run.
Pitch Factor = √(144 + X²) ÷ 12
Where X is the rise in a X/12 pitch
For example, a 6/12 pitch has a factor of about 1.118
Common pitch factors for standard roof pitches:
| Material | Weight/Square | Lifespan | Coverage |
|---|---|---|---|
| 3-Tab Asphalt Shingles | 200-300 lbs | 15-30 years | 3 bundles/square |
| Architectural Shingles | 350-450 lbs | 25-40 years | 3-4 bundles/square |
| Metal Panels | 50-150 lbs | 40-70 years | By panel size |
| Clay/Concrete Tiles | 800-1,200 lbs | 50-100+ years | Based on tile size |
| Slate | 800-1,500 lbs | 75-200+ years | Based on tile size |
| Wood Shingles/Shakes | 200-400 lbs | 25-40 years | 4 bundles/square |
Always include a waste factor when ordering roofing materials to account for:
Recommended waste factors by roof complexity:
A complete roofing project requires more than just the primary roofing material:
Provides a water-resistant barrier beneath the roofing material:
Self-adhering waterproof membrane for vulnerable areas:
Metal components that prevent water infiltration at roof transitions:
Nails or other fastening systems:
Proper roof ventilation is essential for roof longevity:
Our calculator helps you determine the exact amount of roofing materials needed for your project by:
For best results, have your roof measurements and specifications ready before using the calculator. If possible, measure the actual roof surface (not just the building footprint), or provide accurate details about the pitch and complexity.
Remember that roofing is a significant investment and safety-critical aspect of your home. While our calculator provides accurate estimates, we always recommend consulting with a professional roofing contractor for final material quantities and advice on your specific project.
Two sloped sides meeting at a ridge
Ridge length equals house length. Simple to calculate.
All sides slope downward from a ridge or peak
Features hip ridges and potentially valleys. Requires more cutting.
Single sloped plane
Simplest to calculate. No ridges or valleys.
Two slopes on each side (barn style)
Calculate each section separately due to different pitches.
Four double-sloped sides
Complex calculations needed. High waste factor.