Construction/Home calculator
Roofing Calculator Material Estimator
Estimate roof surface area from plan area, pitch factor, and waste allowance.
FormulaRoof area = plan area x pitch factor x (1 + waste %)
Formula
Roofing area estimate
Roof estimates depend on pitch, hips, valleys, overlaps, local codes, and installer recommendations.
Roof area = plan area x pitch factor x (1 + waste %)
100 sq m plan area with 1.12 pitch factor and 10% waste needs about 123.2 sq m.
FAQ6 common questions for this calculator.
FAQs
What is pitch factor?+
Pitch factor adjusts flat plan area to the sloped roof surface area.
Does this estimate shingles or sheets?+
It estimates surface area, which can then be converted to your chosen material coverage.
How does the Roofing Calculator calculate the result?+
For the Roofing Calculator, it uses the Roofing area estimate: Roof area = plan area x pitch factor x (1 + waste %). 100 sq m plan area with 1.12 pitch factor and 10% waste needs about 123.2 sq m.
What information do I need to use the Roofing Calculator?+
For the Roofing Calculator, enter plan area, pitch factor, and waste allowance. Keep the units consistent with the calculator fields and compare your setup with the worked example on the page.
How accurate is the Roofing Calculator?+
Roofing Calculator is a material estimate based on the dimensions, unit system, and allowance values entered. It uses the Roofing area estimate, but cuts, openings, site conditions, pack sizes, and code requirements can change the final quantity.
What should I check before using the Roofing Calculator result?+
For the Roofing Calculator, check plan area, pitch factor, and waste allowance, unit system, waste allowance, openings, site conditions, and supplier pack size. Use the estimate as a planning quantity before ordering materials.
RelatedNearby construction/home calculators for the next step after Roofing Calculator.
Construction/Home calculators to compare next
Construction/Home guide
How to use the Roofing Calculator
Estimate roof surface area from plan area, pitch factor, and waste allowance. The page also explains the roofing area estimate and shows a practical example: 100 sq m plan area with 1.12 pitch factor and 10% waste needs about 123.2 sq m.
- 1
Enter your details
Enter plan area, pitch factor, and waste allowance, then complete any other fields shown in the calculator.
- 2
Check the calculation
Review the result alongside the roofing area estimate: Roof area = plan area x pitch factor x (1 + waste %).
- 3
Compare scenarios
Change one or more inputs to see how they affect the roofing Calculator result before you use the estimate.