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Estimate roof area, roof angle, and materials needed for a typical roof. Use house base area, roof pitch, eaves overhang, and optional price per square foot for fast budget planning. It is useful for DIY planning and DIY cost checks before roofing work begins.
Modify the values and click Calculate. Roof angle and slope correction are computed from pitch automatically. Related: Square Footage Calculator and Concrete Calculator.
Use total roof area to estimate standard material quantities for a typical roofing installation.
*Typical assumptions: 3 bundles per square, 400 ft² per underlayment roll, starter/ridge as broad planning values.
Roof pitch affects actual roof surface area. If you measured a roof horizontally (from drawing or imagery), multiply by the correction factor below.
| Pitch | Angle | Multiply By | Pitch | Angle | Multiply By |
|---|
The calculated area is an estimation. For complex roofs with multiple planes, valleys, and dormers, measure each section separately and sum areas. The Area Calculator can be used to break complex geometry into simple shapes, then aggregate for a more accurate material estimate.
Common roofing materials in the United States include shingles, membrane roofing, and ceramic tile. Typical service life can vary: shingles often 15–30 years, membranes often 5–15 years, and ceramic tile can exceed 100 years in favorable conditions.
Roof pitch is vertical rise divided by horizontal run. In the United States, run is commonly 12 inches. A 7/12 pitch means the roof rises 7 inches for every 12 inches of horizontal run. Outside the U.S., roof angle in degrees is often used.
Pitch influences cost, walkability, drainage, and material selection. Regions with heavy rain or snowfall often use steeper roofs to improve water and snow shedding.
Because pitch changes the true roof surface area, correction factors are essential when converting from horizontal measurements. At very steep pitches, actual area can be substantially larger than the footprint-derived horizontal area.