Convert area to squares
Roofing squares = roof surface area in square feet ÷ 100. Use the measured sloped surface, not the floor area of the home or the horizontal building footprint.
Keep the measured area in the estimate even when you add an ordering allowance. This lets the homeowner or another estimator distinguish actual roof size from extra material for cutting and layout.
Add waste separately
Planned material area = measured area × (1 + waste percentage ÷ 100). For a 2,400-square-foot example: 0% gives 2,400 square feet; 10% gives 2,640; 15% gives 2,760; 20% gives 2,880.
Those percentages are examples, not a recommendation for every roof. Hips, valleys, dormers, product dimensions and the installation layout affect the allowance. Check the takeoff with the installer and supplier.
Read the package coverage
Bundle count = planned material area ÷ coverage per bundle, rounded up to whole bundles. If a product covers exactly 33⅓ square feet per bundle, the 2,640-square-foot example needs 80 bundles after rounding.
Do not assume every shingle, ridge cap or underlayment product has the same coverage. Use the manufacturer’s stated usable coverage, including required laps, and the actual supplier package size.
Area alone is not a complete material order
Starter and drip edge depend on perimeter details. Ridge caps depend on ridge and applicable hip lengths. Valleys and eave protection need their own specifications and quantities.
Use RoofSnap’s area, pitch and edge measurements together with the material calculator. Confirm code requirements, flashing, ventilation, decking repairs and fasteners separately before ordering. A $6.99 roof report supplies measurements, not a complete installation specification.
Sources & further reading
Product details reflect RoofSnap’s current measurement and report workflow. Geometry examples are rounded illustrations, not measurements of the pictured property.
Google Solar API documentation