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Roofing Calculator
Calculate roofing squares, shingle bundles, and installation cost for any roof
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Roofing Calculator
Measure the outer dimensions of the house from the ground
How to Measure Roof Area
Roof area is always larger than the floor footprint below it because of the roof pitch (slope). The steeper the pitch, the larger the actual roof surface. Use a pitch multiplier to convert floor area to roof area.
Roof Area Formula
Roof Area = Floor Footprint × Pitch Multiplier
Squares = Roof Area ÷ 100
Roof Area = Floor Footprint × Pitch Multiplier
Squares = Roof Area ÷ 100
Roof Pitch Multipliers
| Pitch (Rise/Run) | Multiplier | Classification |
|---|---|---|
| 3/12 | 1.031 | Low slope |
| 4/12 | 1.054 | Low slope |
| 6/12 | 1.118 | Medium slope |
| 8/12 | 1.202 | Medium slope |
| 10/12 | 1.302 | Steep slope |
| 12/12 | 1.414 | Steep slope (45°) |
Roofing Material Comparison
- Architectural shingles — Best value, 25–30 yr life, widest color selection
- Metal (standing seam) — Premium longevity (40–70 yrs), energy efficient, higher cost
- Clay/concrete tile — Excellent in hot climates, heavy (need structural check)
- Slate — The ultimate lifespan (100+ yrs), most expensive, requires specialized installers
- Wood shake — Beautiful natural look, requires annual treatment in wet climates
? Frequently Asked Questions
What is a roofing square?
A roofing square equals 100 square feet of roof surface area. Roofing materials like shingles and metal panels are priced and sold by the square. A 2,000 sq ft roof equals 20 squares.
How do I calculate roof area from floor area?
Multiply your home's footprint area by a pitch factor. A 4/12 pitch has a factor of 1.054; a 6/12 pitch = 1.118; an 8/12 pitch = 1.202; a 12/12 pitch = 1.414. Our calculator lets you select the pitch and does this automatically.
How many bundles of shingles per square?
Standard 3-tab asphalt shingles come 3 bundles per square. Architectural/dimensional shingles also come 3 bundles per square, but some heavier products come 4 bundles per square. Always verify with your supplier.
How much does a new roof cost?
A new asphalt shingle roof costs $4–$8 per sq ft installed, or $8,000–$16,000 for a typical 2,000 sq ft home. Metal roofing runs $8–$14/sq ft. Tile is $10–$20/sq ft. Premium materials like slate start at $20/sq ft.
How long do different roofing materials last?
3-tab asphalt: 20–25 years. Architectural asphalt: 25–30 years. Metal (standing seam): 40–70 years. Clay tile: 50–100 years. Slate: 75–150+ years. Wood shake: 20–30 years with maintenance.
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💡 Pro Tips
Always add 10% extra to material estimates to account for waste, cuts, and mistakes.