Roofing Squares & Material Calculator

Calculate roof surface area, roofing squares and common material quantities for a simple gable roof using deterministic geometry.

What this calculator measures

Roof surface area from building length, width and pitch
Roofing squares, where one square equals 100 square feet of roof surface
Shingle bundles using an editable bundles-per-square assumption
Underlayment rolls using editable product coverage
Simple-gable ridge length and drip-edge length

Formula

Pitch factor = √(1 + (rise ÷ 12)²). Roof area = horizontal footprint × pitch factor. Waste is applied after the sloped roof area is calculated.

Important assumptions

This model is for a simple gable roof. Dormers, hips, valleys, additions and irregular planes require field measurements. Product coverage varies, so use manufacturer package values before ordering.

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