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Roofing Calculator
Estimate roof area and roofing material from the size of your house and the roof pitch.
About the Roofing Calculator
Estimate roof area and roofing material from the size of your house and the roof pitch.
How to use the Roofing Calculator
- Enter your House Base Area.
- Choose the Roof Pitch and the Waste Factor.
- Press Calculate Materials.
Formula and method
Roof area = base area × pitch factor, where the factor is √(1 + (pitch ÷ 12)²). Roofing is sold in squares of 100 sq ft.
Worked example
A 1,500 sq ft base with a 6/12 pitch (factor 1.118) has a roof area of about 1,677 sq ft, or 16.8 squares before waste.
Tips
- Steeper roofs need more material.
- Complex roofs with valleys need more waste allowance.
Frequently asked questions
What is a roofing square?
100 square feet of roof.