Roofing Calculator – Squares and Materials
Calculate roofing squares needed and shingles for any roof.
About This Calculator
Estimate materials for equal rectangular roof faces. Enter dimensions measured along the roof surface, not its horizontal footprint. Area = length × surface width × face count. The calculator adds 15% waste, divides by 100 for roofing squares, and rounds bundles up using an assumed three bundles per square. Check the product coverage before ordering. For unequal faces, calculate their areas separately; this simplified form assumes every face has the same dimensions.
Worked Examples
- Area: 2,000 sq ft + 15% waste = 2,300 sq ft
- = 23 squares | 69 bundles
Answer: 23 squares / 69 bundles
- Area: 600 sq ft + 15% = 690 sq ft = 6.9 squares
Answer: 6.9 squares / 21 bundles
- 40x25ft x 4 equal rectangular roof faces: 4,000 sq ft = 40 squares; with 15% waste = 46 squares
Answer: 46 squares / 138 bundles
Who Uses This Calculator?
Estimate shingles for any job.
Understand roofing material quantities.
Bid roofing projects accurately.
Plan roof repair or replacement.
Common Mistakes to Avoid
❌ Forgetting roof pitch factor
Use the actual sloped surface width in this calculator. If you already entered the sloped dimensions, do not add another pitch factor. Horizontal footprint measurements need conversion to roof-surface area first.
❌ Buying exact squares
Always buy 10-15% extra for cuts, waste, ridges, and potential future repairs.
Frequently Asked Questions
What is a roofing square?
100 square feet of roofing. The standard unit for estimating roofing materials.
How many bundles per square?
3 bundles per square for standard 3-tab shingles. Architectural shingles: also ~3 bundles but verify.
Roof lifespan by material?
Asphalt shingles: 20-30 years. Metal: 40-70 years. Tile: 50-100 years. Slate: 75-150 years.