Roofing Calculator
Sloped roof area from the plan area and the pitch, plus waste to order.
Sloped roof area from the plan (footprint) area and the pitch. Add waste before you order sheets or tiles.
Measure
Waste allowance
Roof area
83.5 m²
The sloped area is 83.5 m². With 10% waste, order about 91.9 m².
- Plan area
- 80 m²
- Pitch
- 16.7°
- With waste
- 91.9 m²
- Eaves are included only if they are in the plan area.
- Hips, valleys, and ridge need extra — that is what waste is for.
Roof area83.5 m²
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Worked example
A plan area of 80 m² with a rise of 300 mm over a run of 1,000 mm has a slope factor of about 1.044. The roof area is about 83.5 m². With 10% waste, order about 91.9 m².
FAQ
- What is plan area?
- The flat footprint of the roof, not the sloped surface. The pitch stretches it into the real roof area.
- Does this include eaves?
- Only if they are inside the plan area you enter.
- Is this the area to order?
- The sloped area is the true roof. Add waste for hips, valleys, and ridge before you order sheets or tiles.