Roofing Calculator
Roofing materials are sold by the square (100 sq ft). Enter your roof dimensions and pitch and we'll calculate exactly how many squares, shingle bundles, and rolls of underlayment you need.
How to use this calculator
- One roofing 'square' equals 100 square feet; most architectural shingles cover 1/3 square per bundle.
- Order 10–15% extra for waste, especially on roofs with hips, valleys, or dormers.
- Steeper pitches (above 6:12) require extra labor and safety equipment — factor that into hire bids.
- Always replace flashing and underlayment when you re-shingle; reusing them voids most warranties.
Common mistakes to avoid
- →Forgetting waste and overage. Most pros add 10–15% extra to cover offcuts, mistakes, and damaged material.
- →Measuring once. Always double-check critical dimensions before ordering — returns waste time and money.
- →Ignoring permits and codes. Check with your local building department before purchasing materials for any structural project.
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