Roofing Calculator
Calculate roofing squares, shingle bundles, underlayment, and materials needed for your roofing project.
Roof Dimensions
Pitch affects total roof area
Roof Configuration
Simple gable = 2, hip = 4
Roofing Materials
28 squares
2,772 square feet
How to Calculate Roofing Squares
Roofing materials are measured in "squares." One square equals 100 square feet of roof area. Accurate calculations ensure you order enough materials while avoiding excessive waste and cost.
Roofing Square Formula
Squares = (Total Roof Area ÷ 100) × (1 + Waste Factor)
Account for roof pitch, which increases actual surface area compared to horizontal measurements. A steeper pitch requires significantly more materials.
Roof Pitch Multipliers
- 4:12 pitch: 1.05× multiplier (5% more area)
- 6:12 pitch: 1.12× multiplier (12% more area)
- 8:12 pitch: 1.20× multiplier (20% more area)
- 12:12 pitch: 1.41× multiplier (41% more area)
Shingle Bundle Coverage
Most asphalt shingles are sold in bundles:
- 3-tab shingles: 3 bundles per square (each covers 33.3 sq ft)
- Architectural shingles: 3-4 bundles per square
- Designer shingles: 4-5 bundles per square
Roofing Material Types
Asphalt Shingles
Most common roofing material. 3-tab shingles cost $90-$120 per square. Architectural shingles cost $120-$200 per square. Lifespan 15-30 years.
Metal Roofing
Long-lasting and energy-efficient. Costs $300-$700 per square installed. Standing seam metal is premium option. Lifespan 40-70 years.
Tile Roofing
Clay or concrete tiles. Premium option at $600-$1,200 per square. Extremely durable but heavy—requires structural support. Lifespan 50-100 years.
Additional Roofing Materials
- Underlayment: One 1,000 sq ft roll covers 10 squares (with overlap)
- Ice and water shield: For eaves and valleys
- Ridge cap shingles: Calculate linear feet of ridges and hips
- Drip edge: Linear feet of eaves and rakes
- Roofing nails: 2 lbs per square for hand nailing
- Starter shingles: Linear feet of eaves
Measuring Your Roof
For simple gable roofs: Measure length and width of each plane. Multiply by pitch factor. Add waste (10-15%).
For complex roofs: Break into rectangular sections, calculate each separately, then add together. Include dormers, valleys, and irregular sections.
Important Notes
This calculator provides estimates for material planning. Complex roof designs with multiple valleys, dormers, or irregular shapes require professional measurement for accuracy.
Roofing is dangerous work. Professional installation costs $200-$400 per square for labor. Always use proper safety equipment including harnesses and fall protection.
Steep roofs (8:12 pitch or greater) require additional labor and safety measures, increasing costs 20-50%. Check local building codes for underlayment and ventilation requirements.
Frequently Asked Questions
How do I calculate roofing squares?
One roofing square equals 100 square feet. Divide total roof area by 100 to get squares. Example: A 2,400 sq ft roof = 24 squares. Always add 10-15% for waste, cuts, and ridge caps. Account for roof pitch which increases actual surface area.
How many bundles of shingles per square?
Most asphalt shingles come 3 bundles per square. Each bundle covers approximately 33.3 square feet. Some architectural or designer shingles may have 4 bundles per square—always check the product packaging for exact coverage.
How do I measure roof pitch?
Roof pitch is rise over run, expressed as X:12. A 6:12 pitch rises 6 inches for every 12 inches of horizontal run. Steeper roofs require more materials (pitch multiplier) and higher labor costs. You can measure pitch using a level and measuring tape from inside the attic.
How much does a new roof cost?
Asphalt shingle roofs cost $350-$550 per square installed in Canada (including labor and materials). Materials alone are $90-$150 per square. Metal roofing costs $600-$1,200 per square. Total cost depends on roof size, pitch, complexity, and local labor rates.
How long do asphalt shingles last?
3-tab asphalt shingles last 15-20 years. Architectural (dimensional) shingles last 25-30 years. Premium designer shingles can last 40-50 years. Actual lifespan depends on installation quality, ventilation, climate, and maintenance. Proper attic ventilation extends shingle life significantly.