In the roofing industry, a square is a unit of measurement equal to 100 square feet of roof surface area. It is the standard unit used for estimating material quantities, calculating labor costs, and comparing contractor bids.
When a roofer says a roof is "20 squares," they mean the total roof surface area is 2,000 square feet.
While square feet is a familiar unit, squares simplify the math when ordering materials. A standard bundle of architectural shingles covers approximately 33 square feet — so you need about 3 bundles per square. Knowing your square count makes ordering straightforward.
Measure the length and width of each rectangular section of your roof from the ground or from blueprints. For complex roofs, break the roof into simpler geometric shapes.
Roof surface area is larger than the footprint because of the slope. Multiply your footprint area by the appropriate pitch factor:
Add 10–15% for standard roofs to account for waste from cuts and overlaps. Add 15–20% for complex roofs with multiple valleys, dormers, or steep slopes.
Divide the adjusted square footage by 100 to get the number of squares.
Example: A house with a 40x30 ft footprint (1,200 sq ft) and a 6:12 pitch: 1,200 × 1.118 = 1,342 sq ft. Add 15% waste: 1,342 × 1.15 = 1,543 sq ft. Divide by 100 = 15.43 squares. Order 16 squares.
Manual square calculations depend on accurate footprint measurements, correct pitch identification, and careful arithmetic — all of which introduce potential errors. Studies show that two roofers measuring the same roof manually often differ by 3–8%.
An aerial roof measurement report eliminates these error sources. The calculations are performed by validated software processing thousands of data points from high-resolution imagery.
Your RoofQuantiX report delivers the total square count as well as the breakdown by facet — so you know exactly how much of the roof each section accounts for. The waste factor is calculated based on the actual roof complexity, not a generic estimate.
Accurate square calculations are the foundation of every roofing estimate and material order. Whether you calculate manually or use an aerial measurement report, getting the number right saves money and prevents costly mid-job material shortages.
For most situations, an aerial measurement report from RoofQuantiX is the fastest, most accurate, and most cost-effective way to get the square count you need.