Roof Area & Pitch
Approximate a simple roof area from plan dimensions and pitch.
Result
- Plan area incl. eaves
- 114.81 m²
- Approx. roof surface
- 124.27 m²
FREE ROOF AREA CALCULATOR
Roof Area & Pitch Calculator
Estimate roof surface area from the plan length, width and roof pitch. This gives a practical preliminary quantity for comparing roof areas and discussing roofing materials.
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When this tool is useful
Practical preliminary checks
- Early roof area checks for new homes, extensions and renovations
- Comparing roof material quantities before supplier discussions
- Understanding how a steeper pitch changes roof surface area
- Checking broad roofing quantities against plan dimensions
How it works
The calculator starts with the horizontal plan area and adjusts it using the roof pitch so the sloping roof surface is larger than the plan footprint.
Important estimating note
Real roofs can include hips, valleys, gables, eaves, verandahs, penetrations and separate roof planes. Confirm final roofing quantities from the approved roof plan and supplier or roofing contractor.
Frequently asked questions
How do I calculate roof area from a floor plan?
Start with the horizontal plan area, then adjust for roof pitch. A pitched roof has a larger surface area than the flat plan footprint.
Does roof pitch increase roof area?
Yes. As pitch increases, the sloping roof surface becomes longer and the total surface area increases.
Does this include eaves, hips and valleys?
Use it as a preliminary estimate only. Final roofing quantities should account for the actual roof geometry, eaves, hips, valleys, penetrations, laps and supplier requirements.
Related EBC guidance
Understand the project behind the calculation
Need help applying the numbers to a real building project?
EBC works on renovations, extensions and new builds across Melbourne's Eastern Suburbs.