Shingles and bundles

Roofing Calculator

Convert measured sloped roof area into roofing squares and shingle bundles. Enter the job dimensions below, then review the guide before ordering.

Roofing calculation formula

sloped roof area / 100 x allowance = roofing squares

Worked example: A roof with 1,800 sq ft of sloped area equals 18 squares. With 12% waste, the job needs 20.16 squares, or about 61 bundles when each square uses three bundles.

Use sloped roof area

Roofing is based on the actual roof-plane area, not the building footprint. Measure each plane or calculate slope-adjusted area from reliable plans. Roof measurement involves fall hazards; use safe methods or a qualified professional.

What is a roofing square?

One roofing square covers 100 square feet. Many laminated shingles use three bundles per square, but bundle coverage varies by manufacturer and product. Always check the wrapper or product data.

Waste, ridges, and starter materials

Valleys, hips, dormers, and complex cuts increase waste. Starter strips, ridge caps, underlayment, flashing, fasteners, and ventilation are separate quantities and are not included in the shingle result.

Before placing an order

Recheck field measurements, confirm the selected product's actual package coverage or density, and ask the supplier about order increments, minimum quantities, delivery limits, and return rules. Keep unlike products and assemblies in separate calculations.