Roof Area Calculator
Estimate the true surface area of your roof from your home's footprint and roof pitch — handy for planning a re-roof, restoration or solar installation.
Estimated roof area
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Enter your house length and width to see the estimate.
Results are estimates for planning purposes only. Every roof is different — for exact measurements and a fixed-price quote, book a free on-site inspection or call 0416 689 689.
How this roof area calculator works
Your roof is always larger than your home's floor plan, because it sits at an angle and extends past the walls at the eaves. This calculator takes your house footprint, adds the eave overhang on each side, then divides by the cosine of your roof pitch to convert the flat plan area into the true sloped surface area.
For a simple rectangular home with a gable or hip roof, the result is a solid planning estimate. If your home is L-shaped or has multiple wings, calculate each rectangle separately and add them together.
Why roof area matters
Roof area drives almost every roofing decision: how much material a re-roof needs, how long a restoration will take, how many solar panels can fit, and how much rainwater your gutters have to carry in a downpour. Knowing your approximate area helps you sanity-check quotes and spot numbers that look too good to be true.
Not sure of your roof pitch? Most Australian tiled roofs sit between 20 and 25 degrees, while many metal roofs are shallower. Our roof pitch calculator can work it out from a simple rise-and-run measurement.
Ready To Protect Your Home?
Book Your Free Roof Inspection Today.
Whether you need emergency roofing, leak detection, storm damage repairs or simply peace of mind, our experienced roofing specialists are ready to help. No pressure. No hidden costs. Just honest roofing advice.