CalcuOnline
Real Estate & Civil

Roofing Material Estimator

Sloped roof area, roofing squares, shingle bundles, and underlayment rolls from a building footprint and pitch.

Steeper pitches need more shingles per plan sq ft.

$
Bundles needed
45
Roofing squares
14.8
Underlayment rolls
4
Breakdown
Plan (footprint) area1,200 sq ft
Sloped (actual) roof area1,476 sq ft
Roofing squares (1 square = 100 sq ft)14.76
Estimated shingle cost$1,575.00

Based on standard 3-bundle-per-square asphalt shingles and 400 sq ft synthetic underlayment rolls — adjust for the specific products you’re buying.

Formula

Footprint to sloped area

Sloped area = Plan area × Pitch factor
Plan areaLength × width of the building footprint
Pitch factor√(rise² + run²) ÷ run — steeper pitch, bigger factor
Square100 sq ft of roof coverage, the standard ordering unit
Bundle1/3 of a square for standard asphalt shingles
FAQ

Common questions

A sloped roof has more surface area than the flat footprint below it — the steeper the pitch, the bigger the difference. This tool multiplies the plan (footprint) area by a pitch-specific factor to estimate the actual sloped area that needs covering.

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