What is a roofing square?
A roofing square is 100 square feet of roof surface area. It is the standard unit for ordering shingles and other roofing materials across Canada. To calculate squares, divide your total roof area in square feet by 100.
How many bundles of shingles per square?
For standard 3-tab shingles, you need 3 bundles per square. For architectural (dimensional) shingles, you typically need 4 bundles per square. Always check your product specs, as bundle coverage varies by manufacturer.
How does roof pitch affect material quantities?
Steeper roofs have more actual surface area than their footprint suggests. A 12/12 pitch (45°) increases your material requirement by about 41% compared to a flat measurement. This calculator applies a pitch multiplier to your entered dimensions so your order reflects the actual area to be covered.
How much waste should I add for roofing materials?
Most roofers add 10–15% for standard cuts on straight runs. Add 15–20% for complex roofs with multiple valleys, hips, and ridges where offcuts mount up. When in doubt, use 15% — running short mid-job costs far more than a few extra bundles.
What is ridge cap and how much do I need?
Ridge cap is the row of shingles that covers the peak (ridge) of your roof. It is sold separately in bundles and typically covers about 33 linear feet per bundle. This calculator estimates your ridge cap requirement based on the ridge length across your roof sections.
