Advanced Calculators
Roofing Calculator - Calculate Shingles, Squares & Cost
Calculate roofing materials including shingles, squares, underlayment, and total cost. Supports all roof types and pitches. Get accurate estimates with waste factor and material breakdown.
Use Roofing Calculator - Calculate Shingles, Squares & Cost to get instant results without uploads or sign-ups. Everything runs securely in your browser for fast, reliable output.
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About this tool
Our Roofing Calculator is the most comprehensive free tool for estimating roofing materials for any project. Whether you're replacing shingles on a simple gable roof, installing a new roof on a complex hip design, or planning a complete re-roof with new underlayment and flashings, this calculator provides accurate estimates for all materials needed. Understanding roof area is critical because roofing materials are sold by the "square" - one square equals 100 square feet of roof area. The calculator converts your roof dimensions into squares and calculates the exact number of shingle bundles needed (typically 3-4 bundles per square depending on shingle type).
Roof pitch (slope) significantly affects material requirements. A steeper pitch means more surface area than the flat footprint suggests. Our calculator uses the pitch multiplier method to accurately account for slope - a 4:12 pitch adds about 5% area, while a steep 12:12 pitch adds 41% area compared to a flat roof. This is crucial for accurate estimates. The calculator supports common roof types including gable (two sloped sides), hip (four sloped sides), gambrel (barn-style with two pitches), and flat roofs. Each type has different geometric calculations to determine total surface area.
Beyond shingles, the calculator estimates all necessary materials: underlayment (felt or synthetic), starter strips, ridge cap shingles, drip edge, valley flashing, and roofing nails. Waste factors are built in - typically 10% for simple roofs, 15% for complex roofs with multiple valleys and dormers. The cost estimation breaks down expenses by material category, helping you budget accurately and compare quotes from roofing contractors. You can estimate costs using price per square (common for labor quotes) or price per bundle (for DIY material purchases).
All calculations follow roofing industry standards and building codes. The tool accounts for important details like ridge cap coverage (typically 33 linear feet per bundle) and nail requirements (approximately 2 pounds per square). It's completely free, requires no registration, and works entirely in your browser. Perfect for homeowners planning roof replacement, contractors estimating jobs, insurance adjusters calculating claims, and DIYers tackling their own roofing projects.
Usage examples
Simple Gable Roof
30 ft × 40 ft, 6:12 pitch, architectural shingles
Area: 13.4 squares, Bundles: 40, Underlayment: 15 rolls
Hip Roof
40 ft × 50 ft, 4:12 pitch, 3-tab shingles
Area: 21.7 squares, Bundles: 65, Ridge cap: 12 bundles
Steep Gable Roof
25 ft × 35 ft, 12:12 pitch, premium shingles
Area: 12.3 squares, Bundles: 37, Underlayment: 14 rolls
Gambrel Barn Roof
30 ft × 60 ft, mixed pitch, architectural
Area: 24.5 squares, Bundles: 74, Complex calculation
How to use
- Select your roof type (Gable, Hip, Gambrel, or Flat)
- Enter roof dimensions: length, width, and ridge length
- Specify roof pitch (e.g., 4:12, 6:12, 8:12)
- Choose shingle type (3-tab, Architectural, or Premium)
- Enter material prices per bundle or square
- View complete material list with squares, bundles, and total cost
Benefits
- Accurate square footage for any roof type
- Automatic pitch multiplier calculations
- Complete material list: shingles, underlayment, accessories
- Built-in waste factor (10-15%) for realistic estimates
- Support for all common roof types and pitches
- Ridge cap and valley calculations
- Cost breakdown by material category
- Instant calculations as you adjust dimensions
- Compare 3-tab, architectural, and premium shingles
- Mobile-friendly for on-site measurements
- No registration required - completely free
- Based on professional roofing standards
FAQs
How many bundles of shingles are in a square?
Standard 3-tab shingles have 3 bundles per square. Architectural (dimensional) shingles typically have 3 bundles per square, but heavier premium shingles may have 4-5 bundles per square. Always check the manufacturer specifications, as coverage varies by product. One square covers 100 square feet of roof area.
What is roof pitch and how do I measure it?
Roof pitch is the slope expressed as rise over run, typically shown as X:12 (e.g., 6:12 means 6 inches of rise for every 12 inches of horizontal run). To measure: use a level and tape measure from the roof surface, or calculate from attic measurements. Common pitches are 4:12 (moderate), 6:12 (standard), and 8:12 (steep). Pitch affects material quantity and installation difficulty.
How much waste factor should I add for roofing?
Add 10% waste for simple gable or hip roofs with few penetrations. Add 15% for complex roofs with multiple valleys, dormers, skylights, or irregular shapes. Add 20% for very complex roofs or if using decorative patterns. Waste accounts for cutting around vents and chimneys, starter strips, and damaged or dropped shingles.
What is the difference between 3-tab and architectural shingles?
3-tab shingles are single-layer, flat, and economical ($70-100 per square), lasting 15-20 years. Architectural shingles are multi-layered, dimensional, and more durable ($100-150 per square), lasting 25-30 years. Architectural shingles look better, resist wind better, and add more home value, but cost 20-40% more than 3-tab.
How much does a new roof cost?
Roof replacement costs $5,000-15,000 for average homes (1,500-2,500 sq ft). Materials run $3,000-7,000 depending on shingle type. Professional installation adds $3-5 per square foot ($3,000-10,000 labor). Premium materials, steep pitch, and complex designs increase costs. DIY can save 50% but requires skills, tools, and safety equipment. Always get 3+ quotes from licensed roofers.
What materials do I need besides shingles?
Complete roof replacement requires: shingles, underlayment (felt or synthetic), starter strips, ridge cap shingles, drip edge (eaves and rakes), valley flashing, step flashing (chimneys/walls), roofing nails, roof cement/sealant, and vent boots. Our calculator estimates most materials. Also consider: ice & water shield for eaves/valleys, ventilation requirements, and permits required by local building codes.
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