Construction · Roofing · Materials
Roofing
Calculator
Calculate roof area from footprint and pitch, find shingle squares and bundles needed, estimate material costs, and explore pitch conversions with a visual roof diagram.
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Roof Area (ft²)
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Squares
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Bundles
Roof Area from Footprint + Pitch
Enter your house footprint and roof pitch. The pitch multiplier converts flat area to actual sloped surface area.
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ft
:12
in
Common Pitches
Shingles, Squares & Bundles
A roofing "square" = 100 sq ft. Standard asphalt shingles come 3 bundles per square.
ft²
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bundles
Roof Pitch Calculator
Convert between pitch formats: X:12, percent grade, degrees, and pitch multiplier.
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°
Load presets
Roof Type Area Calculator
Different roof shapes need different area calculations. Select your roof type.
Roof Area
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sq ft
Squares
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Bundles
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Roof Cross-Section
Roof Area
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Pitch Multiplier
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Squares
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Est. Cost
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Roofing Estimate
📋 Pitch Reference Table
Roof Area & Roofing Calculations
Roofing calculations start with the roof's footprint (horizontal area), then apply the pitch multiplier to get the actual sloped surface. A 6:12 pitch has a multiplier of 1.118, meaning a 1,000 sq ft footprint has 1,118 sq ft of actual roof surface.
Key Formulas
Pitch Multiplier = √(1 + (pitch/12)²)
Roof Area = Footprint × Pitch Multiplier
Roofing Square = 100 sq ft of roof area
Bundles = ceil(Squares × bundles_per_square × (1 + waste%))
Pitch Angle = arctan(rise/12) [degrees]
Pitch % = (rise/12) × 100
Common pitch multipliers:
3:12 → 1.031 | 4:12 → 1.054 | 5:12 → 1.083
6:12 → 1.118 | 8:12 → 1.202 | 12:12 → 1.414
What is a roofing square?
A roofing square is 100 square feet of roof area. Roofing materials are typically sold and estimated in squares. For example, a 2,000 sq ft roof = 20 squares. Standard 3-tab asphalt shingles require 3 bundles per square (each bundle covers about 33 sq ft). Dimensional or architectural shingles may require 4 bundles per square. Always add 10–15% for waste, ridge caps, starter strips, and cuts around vents and valleys.
How does roof pitch affect material quantity?
Higher pitch = more actual surface area than footprint suggests. A flat roof (0:12) has a multiplier of 1.0 (footprint = roof area). A 6:12 pitch has multiplier 1.118 (roof area is 11.8% more than footprint). A 12:12 pitch (45°) has multiplier 1.414 (41.4% more material). This matters for budgeting: a 2,000 sq ft house footprint with a steep 12:12 pitch needs 2,828 sq ft of shingles — 41% more than you'd expect from measuring the floor plan.
What pitch is best for my roof?
Pitch choice depends on climate, style, and material: Low pitch (2:12–4:12) — modern/flat look, lower material cost. Moderate pitch (4:12–8:12) — most common residential, good drainage, most materials suitable. Steep pitch (9:12+) — traditional/colonial look, excellent drainage, highest material cost. For snow-heavy climates, at least 4:12 is recommended to shed snow. Low pitches need special low-slope roofing materials. Minimum pitch for standard asphalt shingles is 2:12 (with double-layer underlayment) or 4:12 standard.
How long do different roofing materials last?
Typical lifespans: 3-tab asphalt shingles: 15–20 years. Architectural/dimensional shingles: 25–30 years. Metal roofing (steel/aluminum): 40–70 years. Clay or concrete tile: 50–100 years. Slate: 75–150+ years. Wood shingles/shakes: 25–30 years. Flat roof (TPO/EPDM): 15–25 years. Cost vs lifespan matters: metal roofing costs 3–5× more than asphalt but lasts 3× longer, often making it more economical over 50 years.