Roofing Calculator
Estimate shingles, underlayment, and roofing costs
Length of the roof base
Width of the roof base
Rise per 12" run (e.g., 6 for 6/12)
Base Area
—
sq ft
Actual Roof Area
—
sq ft
Roofing Squares
—
squares
Shingle Bundles
—
bundles
Estimated Cost
—
USD
Disclaimer: Results are estimates based on standard formulas. Not a substitute for professional advice from a licensed contractor, engineer, or architect. Verify all calculations before making purchasing or construction decisions.
How to Use This Calculator
Planning a roofing project? Accurate material estimates prevent costly over-ordering. Our calculator accounts for roof pitch to give you true surface area.
- Measure the length and width of your roof at the base
- Determine your roof pitch
- Enter dimensions in the calculator
- Add 10-15% for waste, valleys, and ridges
Expert Insights
Smart analysis for your Roofing project
Pitch-to-Cost Analysis
Steep roofs (8/12+) need 20-40% more material and higher labor costs. Our AI adjusts estimates based on your exact pitch ratio.
Waste Factor Intelligence
Gable roofs: 10-15% waste. Hip roofs: 15-20%. Complex roofs with dormers: 20-25%. AI selects the right factor for your roof type.
Climate Zone Recommendations
Ice & water shield required in northern zones. AI checks your region's IRC climate zone for code-compliant underlayment suggestions.
Calculation Formula
Pitch factor = sqrt(pitch^2 + 144) / 12
Roof area = Base area x Pitch factor
Squares = Roof area / 100
Bundles = Squares x 3 x 1.1 (includes 10% waste)
Roofing Material Comparison
| Material Type | Lifespan | Cost per Square | Bundles/100 sq ft | Waste Factor |
|---|---|---|---|---|
| 3-Tab Asphalt | 15-25 years | $80-120 | 3 | 10-15% |
| Architectural Shingles | 30-50 years | $120-200 | 3-4 | 12-18% |
| Premium Designer | 40-50+ years | $200-400 | 4-5 | 15-20% |
| Metal Standing Seam | 40-70 years | $500-1,200 | N/A (panels) | 5-10% |
Authority References
Our calculations are based on guidelines and standards from these authoritative sources:
- National Roofing Contractors Association (NRCA) — Roofing Manual & Installation Guidelines. Learn more
- Asphalt Roofing Manufacturers Association (ARMA) — Residential Asphalt Roofing Manual. Learn more
- International Residential Code (IRC) — Chapter 9 — Roof Assemblies. Learn more
Frequently Asked Questions
How many bundles of shingles do I need?
You need 3 bundles of standard 3-tab shingles per roofing square (100 sq ft). For architectural shingles, you may need 4 bundles per square.
What is a roofing square?
A roofing square equals 100 square feet of roof area, the standard unit for measuring and pricing.
How much does a new roof cost?
Average roof replacement costs $5,000-$12,000 for asphalt shingles, $12,000-$25,000 for metal, and $20,000+ for slate or tile.