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Calculate asphalt shingles needed for your roof. Enter roof area and bundle coverage to get shingle bundles, squares, and waste allowance for reroofing.
Convert roof pitch rise and run to angle, percent slope, and pitch factor. Essential for roofing material estimates, rafter layout, and drainage design.
Size gutters and downspouts from roof area and rainfall intensity. Calculate required gutter capacity, downspout count, and K-style or half-round sizing.
Convert footprint to surface area with pitch factor, then to squares and bundles with 10% waste.
Bundles = (Area × Pitch Factor ÷ 100) × Bundles/Square × 1.10Synthetic underlayment rolls cover 10–12 squares (1,000–1,200 sq ft). Order one roll per 10 squares minimum.
Rolls = ceil(Roof Area ÷ Roll Coverage)Apply 3–6 ft wide ice barrier at eaves in cold climates. Valleys get full run of 36″ wide membrane.
LF = Eave Length + Valley Length × 2 (width per code)Updated: July 2026
≈2,108 sq ft surface: 64 bundles shingles, 2 underlayment rolls, ice shield at 120 LF eaves, drip edge at eaves and rakes.
Add 60 LF valley ice and water shield beyond eave protection. Valley metal or woven shingles per install method.
Calculate ridge + hip total LF for cap shingles. Hip roofs use more cap units than simple gable ridge only.
Generate a complete material list for asphalt shingle roof replacement beyond bundles alone. Enter roof area, pitch, and linear feet of eaves, valleys, and ridges for underlayment rolls, ice barrier, drip edge, and nail counts.