Roofing Calculator
Calculate roof area, roofing squares, shingle bundles, and total cost from your building footprint and roof pitch.
Input Parameters
Roof Area (sq ft)
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Roofing Squares
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Shingle Bundles
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Estimated Cost
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Detailed Breakdown
Pitch Multiplier
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Base Area
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Waste Area
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Felt Rolls (15#)
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Drip Edge (ft)
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Nails (lbs)
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About This Calculator
This roofing calculator converts your building footprint to actual roof area using pitch multipliers. A roofing "square" covers 100 sq ft, and each square typically requires 3 bundles of standard three-tab shingles. The waste factor accounts for cuts, valleys, and hips.
Adds your roofing takeoff into the Construction Estimate Builder.
Saved Calculations
How Roofing Estimates Work
Measure the Footprint
Measure the length and width of your building at ground level. Multiply to get the total footprint in square feet. For complex shapes, break into rectangles and add them.
Apply the Pitch Multiplier
Roof pitch (rise over 12" run) determines how much larger the roof surface is vs. the flat footprint. A 4/12 pitch adds about 5.4%; a 12/12 (45-degree) pitch adds 41.4%.
Calculate Squares and Bundles
One roofing "square" = 100 sq ft. Standard 3-tab shingles require 3 bundles per square. Architectural shingles may need 4-5 bundles per square. Always add 10-15% for waste.
Common Roof Pitch Guide
Frequently Asked Questions
How many bundles per square?
Standard 3-tab shingles: 3 bundles/square. Architectural shingles: 4-5 bundles/square. Always buy an extra bundle or two for ridge caps and mistakes.
What does "cost per square" include?
Material cost per square varies: $80-$100 for 3-tab, $100-$150 for architectural, $250-$400 for metal. Labor adds $150-$300 per square depending on pitch and region.
Should I add underlayment cost?
Yes. Synthetic underlayment runs $0.15-$0.25/sq ft. Ice and water shield for eaves costs $1-$2/sq ft. Budget about $50-$75 per square for underlayment.