Roofing Calculator
Estimate roof surface area, shingle bundles and underlay needed from footprint and pitch.
Calculate the true roof surface area from the building footprint and roof pitch, plus the materials needed to cover it.
How to use it
- 1Enter the roof footprint area.
- 2Select or enter the roof pitch.
- 3Set a waste percentage and coverage per bundle.
Roof details
Enter the roof footprint, pitch and shingle coverage.
Result
Roof area
121.4 m²
- Roofing squares
- 13.07
- Bundles needed
- 40
- Estimated cost
- €1,400.00
A roofing square covers 9.29 m² (100 sq ft); order a spare bundle for cuts and ridges.
Frequently asked questions
- What is a pitch multiplier?
- A factor that converts flat footprint area to actual sloped roof area; steeper roofs have a bigger multiplier.
- How much waste should I allow?
- 10–15% is typical to cover cuts, ridges and hips.
- Does this work for metal roofing?
- Yes, adjust the coverage-per-unit field to match your sheet size.
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