Roofing Calculator
Calculate roofing squares, bundles of shingles, and materials based on roof dimensions and pitch.
Results
How to Calculate Roofing
Multiply footprint length by width. Apply pitch multiplier to get actual roof area. Add waste factor. Divide by 100 for roofing squares. Multiply squares by 3 for bundles of shingles.
Frequently Asked Questions
How many bundles of shingles do I need?
Three bundles cover one roofing square (9.3 m² / 100 sq ft). A 200 m² roof at 6/12 pitch has roughly 224 m² of actual surface, needing about 24 squares or 72 bundles.
How do I calculate roof pitch?
Pitch is expressed as rise over run (e.g. 6/12 means 6 units of rise for every 12 horizontal). A steeper pitch increases actual roof area. Multiply the footprint area by the pitch factor to get true surface area.
How much does a new roof cost?
Asphalt shingles: $4-$7 per sq ft installed. Architectural shingles: $5-$9. Metal roofing: $7-$14. Tile or slate: $12-$25. A typical 2,000 sq ft roof costs $8,000-$14,000 for asphalt or $14,000-$28,000 for metal.
How long do roofing materials last?
3-tab asphalt shingles: 15-20 years. Architectural shingles: 25-30 years. Metal roofing: 40-70 years. Clay/concrete tile: 50-100 years. Slate: 75-200 years. Warranties vary — check manufacturer specs.
What is a roofing square?
A roofing square equals 100 square feet (9.29 m²) of roof area. Materials are priced and sold by the square. One square of 3-tab shingles weighs about 200-250 lbs (90-113 kg); architectural shingles weigh 250-400 lbs per square.