Satellite Roofing Calculator
1,341.64 sq ft of roof
13.42 squares (roof area 1341.64 sf = footprint × 1.12 slope factor); 1475.8 sf with 10% waste.
- Sloped area = footprint × √(1+(rise/12)²) = 1200 × 1.12. Pure geometry: include eave/rake overhangs in your footprint or this understates.
- Waste: 10% for simple gable (JLC convention). Waste is a range by design; cut-up roofs can exceed 15%.
- Footprint estimation fails on complex plans (dormers, turrets, intersecting gables); measure each roof plane there instead.
- A 4/12-vs-8/12 pitch mistake is a 14% area error: verify pitch, don't guess it.
Why This One Is Different
If you searched “satellite roofing calculator,” you probably wanted an aerial-imagery report: a service that measures every plane of your roof from a photo, the way RoofSnap-class tools do for insurance and contractor estimates. That is not what this calculator does, and pretending otherwise would hand you a worse number with more confidence attached. Instead, it works from footprint times width, times the pitch slope factor, for sloped area. It's fast and free, but honest about its limit: it cannot see a dormer, a turret, or an intersecting gable the way a photo can. For a simple rectangular roof it's accurate; for anything more complex, this page tells you when it's worth paying for the aerial version instead.
Where the Numbers Come From
- Sloped roof area = footprint × √(1+(rise/12)²): pure geometry, and one of the few takeoff numbers that doesn't need a variance band once pitch is confirmed. Source: slope-factor geometry, verified against Roof Online pitch-factor table / JLC Asphalt Shingles Field Guide
- Footprint-based estimation fails on complex plan geometry (dormers, turrets, and intersecting gables) because a single rectangle can't represent multiple roof planes; measure each plane separately (or get an aerial report) in that case. Source: roof-area quantity-takeoff convention (JLC field guide, footprint-model limits)
- Aerial-imagery measurement services (RoofSnap-class reports) digitize each individual roof plane from satellite or drone photos and are the accurate route for complex roofs or insurance-grade documentation: a different product category from a footprint calculator. Source: supplier estimating practice (RoofSnap-class aerial measurement services)
- Worked example: a 45×28 ft footprint at 5/12 pitch = 1,260 sf × 1.083 = 1,364.6 sf = 13.65 squares before waste: no imagery involved, just the two footprint dimensions and the pitch. Source: worked example, closed-form geometry
More Questions
When should I pay for an aerial roof report instead?
When the roof has more than one plane, when you need documentation for an insurance claim, or when the material order is large enough that a 5-10% measurement error is expensive. Simple gable or hip roofs rarely need it.
Related Calculators
Formulas, waste factors, and cost models on this page follow the sourced conventions on our methodology page. Estimates only; verify with your supplier and local code.