Roofing Calculator
Estimate Roofing by entering project dimensions. Get material quantities, coverage areas, and cost breakdowns for accurate purchasing and budgeting.
Formula
Roof Area = Footprint × Pitch Factor × (1 + Waste%)
Calculate roof footprint, apply the pitch multiplier for slope, then add waste factor. Divide total area by 100 to get squares. Multiply squares by 3 for shingle bundles.
Worked Examples
Example 1: Simple Gable Roof
Problem:Calculate materials for a 40×30 ft house with 6:12 pitch gable roof.
Solution:Footprint area = 40 × 30 = 1,200 sq ft\n\nApply pitch factor (6:12 = 1.118):\nRoof area = 1,200 × 1.118 = 1,342 sq ft\n\nAdd 10% waste:\nTotal area = 1,342 × 1.10 = 1,476 sq ft\n\nSquares = 1,476 ÷ 100 = 14.76\nShingle bundles = 15 × 3 = 45 bundles\nFelt rolls = 1,476 ÷ 400 = 4 rolls
Result:15 squares, 45 bundles shingles, 4 rolls felt
Example 2: Hip Roof Calculation
Problem:Calculate for a 50×35 ft hip roof with 8:12 pitch.
Solution:Footprint = 50 × 35 = 1,750 sq ft\n\nHip roof factor: 1.05\n1,750 × 1.05 = 1,838 sq ft\n\nPitch factor (8:12 = 1.202):\n1,838 × 1.202 = 2,209 sq ft\n\nAdd 15% waste (hip roofs have more cuts):\n2,209 × 1.15 = 2,540 sq ft\n\nSquares = 25.4 ≈ 26 squares
Result:26 squares needed (~78 bundles shingles)
Example 3: Cost Estimation
Problem:Estimate total cost for 20-square roof replacement with architectural shingles.
Solution:Materials:\nShingles: 20 × 4 bundles × $45 = $3,600\nUnderlayment: 5 rolls × $30 = $150\nRidge caps: 2 bundles × $50 = $100\nFlashing, nails, misc: $300\nTotal materials: $4,150\n\nLabor: 20 squares × $100 = $2,000\n\nTotal: $4,150 + $2,000 = $6,150
Result:Approximately $6,150 for materials and labor
Frequently Asked Questions
What roofing materials are available?
Common options: Asphalt shingles (20-30 years, most affordable), Architectural shingles (30-50 years, more durable), Metal roofing (40-70 years, energy efficient), Wood shakes (20-40 years, natural look), Clay/concrete tiles (50-100 years, heavy), Slate (75-200 years, premium). Choose based on budget, climate, and home style.
What is roofing underlayment?
Underlayment is a waterproof barrier installed between roof deck and shingles. Types: Felt paper (traditional, affordable), Synthetic (more durable, tear-resistant), Ice and water shield (self-sealing, for leak-prone areas). Required by code in most areas. Protects if shingles are damaged. Install in valleys, around penetrations, and at eaves in cold climates.