Roofing Calculator

Estimate roofing materials and cost by roof size, pitch, and material type (asphalt, metal, tile).
ft
ft
Roof Pitch
Roofing Material

Use the Roofing Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

A Roofing Calculator estimates the materials needed and the cost of a new roof. This is crucial for budgeting, preventing material shortages or over-ordering, and ensuring accurate quotes from contractors.

It typically uses the roof's dimensions (length, width, pitch) to calculate the total square footage. This area is then divided by the coverage per unit of material (e.g., squares per bundle of shingles) to determine the quantity required.

Always measure carefully, accounting for eaves and overhangs. Don't forget to factor in waste percentages (typically 10-15%) for cuts and errors, especially with complex roof designs.

Example: Estimating Shingles for a Simple Gable Roof

  1. 1 You have a rectangular roof section that is 40 feet long and 25 feet wide (slope length). The shingle bundles you plan to use cover 33.3 square feet per bundle, and the cost is $30 per bundle. You want to include a 10% waste factor.
  2. 2 1. Calculate total roof area: 40 ft * 25 ft = 1000 sq ft. 2. Add waste factor: 1000 sq ft * 1.10 = 1100 sq ft (adjusted area). 3. Calculate bundles needed: 1100 sq ft / 33.3 sq ft/bundle ≈ 33.03 bundles. Round up to 34 bundles. 4. Calculate total material cost: 34 bundles * $30/bundle = $1020.
  3. 3 You will need approximately 34 bundles of shingles, costing $1020, to cover your roof with a 10% waste factor included.
  4. 4 This calculation provides a solid estimate for shingle purchasing. Remember this doesn't include other materials like underlayment, drip edge, or labor costs, which would need separate estimations.

Source: HomeAdvisor · Last updated: April 2026

Frequently Asked Questions

How much does a new roof cost?
Average costs: asphalt shingles $5,000-$12,000, architectural shingles $7,000-$15,000, metal roofing $10,000-$25,000, and tile $15,000-$35,000 for a typical 1,500-2,000 sq ft roof. Costs vary by region, pitch, and complexity.
How do I calculate how many squares of roofing I need?
One roofing "square" covers 100 square feet. Measure the roof area (or estimate from the footprint multiplied by a pitch factor) and divide by 100. Add 10-15% for waste. A 2,000 sq ft roof needs about 20-23 squares.
How long does a roof last?
Three-tab asphalt shingles last 15-20 years, architectural shingles 25-30 years, metal roofing 40-70 years, and tile or slate 50-100+ years. Lifespan depends on climate, ventilation, and maintenance.

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