Calculate roof area using pitch formula: Area = Footprint / Cos(Pitch).
Not sure what the angle is? Compare common slopes visually below.
The area of a roof is calculated by dividing the base area (footprint) by the cosine of the roof pitch.
Equation: Area = Base Area / Cos(Pitch)
The most common roof pitch in residential construction is between 10° and 25°.
A pitch of 4/12 (approx 18.4°) is considered a low-pitch roof, while 12/12 (45°) is steep. Steeper roofs are necessary in areas with heavy snowfall to prevent collapse.
Calculate the roof area using this tool, then multiply by the unit price (per square meter or square foot) of your chosen material.
Materials: $2-$4 per sq ft is common for asphalt shingles.
Labor: Add 40-60% to material cost for a complete estimate.
Yes, steeper roofs require more labor time to install safely and may use slightly more material due to complex cutting. However, low-pitch roofs (flat or nearly flat) require more material per square foot to waterproof effectively.