Roofing Squares and Bundles

Squares, bundles per shingle product, underlayment rolls, drip edge.

Run the calculator

Example

You enter

Roof area (ft²) 2200
Pitch rise (in / 12) 6
Shingle product architectural
Perimeter (ft) 200

You get

Squares 24.6
Bundles 74
Underlayment rolls 7
Drip edge / starter (lf) 200
Starter strip (LF) 200
Waste factor 0.12

Details, formula, and sources

Squares = roof_area / 100 ft² + pitch-based waste factor; bundles = squares × bundles_per_square (typically 3 for 3-tab, 3-4 for architectural). Underlayment + drip edge from linear quantities.

ARMA (Asphalt Roofing Manufacturers Association) Residential Asphalt Roofing Manual by name. IRC 2021 (International Residential Code). §R905.

ARMA manuals free at asphaltroofing.org. Free read-only access at codes.iccsafe.org.

Estimate. AHJ and licensed professional govern.

Field names used by the API: roof_area_ft2, pitch_rise, shingle_product, perimeter_ft, squares, bundles, underlayment_rolls, drip_edge_lf, starter_strip_lf, waste_factor

Pitch-based waste factor 8% (≤ 6/12) / 12% (8-9/12) / 17% (≥ 10/12)ARMA / engineering practice