Roof Size Calculator
Calculate roof area for materials and cost estimation.
ft
ft
in
Roof Area = (Length + Overhang) x (Width + Overhang) x Pitch Multiplier x Waste Factor
Example: 2,000 sq ft home with 6/12 pitch roof = 2,236 sq ft roof area. You'll need about 23 squares (2,300 sq ft) of shingles with waste
What is a roofing square?
A roofing square is 100 square feet. Roofing materials like shingles are sold by the square. Most shingle bundles cover 1/3 of a square (33.3 sq ft).
How does roof pitch affect area?
Steeper roofs have more surface area than flat roofs over the same footprint. A 12/12 pitch (45x) has about 41% more area than a flat roof.
Why add a waste factor?
Waste accounts for cuts, overlaps, starter strips, and mistakes. Simple gable roofs need less waste (10%), while complex roofs with many hips and valleys need more (20%+).
📐 Formula
Roof Area = (Length + Overhang) x (Width + Overhang) x Pitch Multiplier x Waste Factor
📝 Example Calculation
Example: 2,000 sq ft home with 6/12 pitch roof = 2,236 sq ft roof area. You'll need about 23 squares (2,300 sq ft) of shingles with waste
❓ Frequently Asked Questions
What is a roofing square?▼
A roofing square is 100 square feet. Roofing materials like shingles are sold by the square. Most shingle bundles cover 1/3 of a square (33.3 sq ft).
How does roof pitch affect area?▼
Steeper roofs have more surface area than flat roofs over the same footprint. A 12/12 pitch (45x) has about 41% more area than a flat roof.
Why add a waste factor?▼
Waste accounts for cuts, overlaps, starter strips, and mistakes. Simple gable roofs need less waste (10%), while complex roofs with many hips and valleys need more (20%+).