Roofing Calculator

Accurately estimate the surface area of your roof and the quantity of shingles or other materials required for your project.

House Footprint / Base Area (sq ft)*

Roof Pitch (x:12)*

Waste Factor (%)*

Roofing Formula: 1. Actual Roof Area = Base Area × Pitch Multiplier 2. Total Area = Actual Area × (1 + Waste Factor) 3. Squares = Total Area ÷ 100 (Pitch multiplier = sqrt(1 + (Pitch/12)²))

A 2,000 sq ft house with a 6:12 pitch (1.118 multiplier) and 10% waste: • Actual Area: 2,000 × 1.118 = 2,236 sq ft • Total Area: 2,236 × 1.1 = 2,460 sq ft • Squares: 2,460 ÷ 100 = 24.6 Squares

What is a "Square" in roofing?

In the roofing industry, a "square" is a unit of area equal to 100 square feet. Most roofing materials, like shingles and underlayment, are sold by the square.

How does roof pitch affect the area?

The pitch (or slope) of a roof increases the actual surface area compared to the flat footprint (base area) of the house. A steeper roof has a larger surface area for the same house footprint. This calculator uses a "pitch multiplier" to account for this increase.

How much waste should I account for?

Standard roofing practice is to add 10% to 15% for waste, cutting, and overlapping. For complex roofs with many valleys and hips, you might need up to 20% waste factor.

What is included in a roofing estimate?

A basic estimate includes the main field shingles, starter shingles, hip and ridge caps, underlayment, and nails. This tool provides a primary estimate for the main surface materials.

🔗 Related Calculators

📐 Formula

Roofing Formula: 1. Actual Roof Area = Base Area × Pitch Multiplier 2. Total Area = Actual Area × (1 + Waste Factor) 3. Squares = Total Area ÷ 100 (Pitch multiplier = sqrt(1 + (Pitch/12)²))

📝 Example Calculation

❓ Frequently Asked Questions

What is a "Square" in roofing?▼

In the roofing industry, a "square" is a unit of area equal to 100 square feet. Most roofing materials, like shingles and underlayment, are sold by the square.

How does roof pitch affect the area?▼

How much waste should I account for?▼

Standard roofing practice is to add 10% to 15% for waste, cutting, and overlapping. For complex roofs with many valleys and hips, you might need up to 20% waste factor.

What is included in a roofing estimate?▼

A basic estimate includes the main field shingles, starter shingles, hip and ridge caps, underlayment, and nails. This tool provides a primary estimate for the main surface materials.