Roofing Area Calculator
Roof area is larger than the footprint because of the slope. A pitch factor adjusts the flat area to the actual roof surface. This calculator estimates the total roof area for material ordering.
What Is Roofing Area?
Roof area is the actual surface area of a sloped roof, calculated by multiplying the flat footprint area by a pitch factor. The pitch factor accounts for the slope and ranges from 1.0 for flat roofs to about 1.4 for steep roofs. Accurate roof area is essential for ordering shingles, tiles, or metal sheets.
Example
Formula: Length x Width x Pitch factor = 8 m x 6 m x 1.1 pitch factor = 52.80 m²
Enter length and width units and a pitch factor, then the result will be in m².
Tip: Choose your result unit on the right before calculating.
Step-by-step calculation
- Enter a pitch factor for slope and calculate to see roof area in m².
How this is calculated
Roof area = plan area divided by cos(pitch) for pitched roofs, or rafter length times width; we use the roof pitch to convert the flat (plan) area to the true sloping surface area.
Sources: Manufacturer roof pitch and slope guidelines.
FAQ
- How do I calculate roof area by hand?
- Multiply length x width x pitch factor. Example: 8 m x 6 m x 1.1 = 52.8 m².
- What is the formula for roof area?
- Area = Length x Width x Pitch factor. Use a pitch chart to find your factor.
- Gable roof vs hip roof area
- Gable roofs use one pitch factor; hip roofs are more complex and may need a professional estimate.
- What units should I use?
- Use meters for dimensions and m² for result. The pitch factor is unitless.
- Can I use this for a shed roof?
- Yes. Enter length, width, and pitch factor for a single-slope shed roof.