Roofing Calculator

Estimate roofing materials and cost by roof size, pitch, and material type (asphalt, metal, tile).

By Konstantin Iakovlev · Updated September 2026 · Source: HomeAdvisor

ft
ft
Roof Pitch
Roofing Material

Roof Area

1,344 sq ft

Squares Needed

14

42 bundles

Total Est. Cost

$8,176.00

Roofing Estimate

Footprint Area1,200 sq ft
Roof Area (with pitch)1,344 sq ft
Roofing Squares14 squares
Bundles (3/square)42 bundles
Material Cost (Asphalt Shingles)$5,376.00
Labor Cost$2,800.00
Total Estimated Cost$8,176.00

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. Results are estimates from the numbers you enter and the assumptions described on this page; check them against local building codes, product specifications and current prices, and have structural, electrical or gas work designed or checked by a licensed professional.

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 multiplies the roof's footprint (length × width, including overhangs) by a pitch factor, 1.03 for a 3:12 roof, 1.12 for 6:12 and 1.25 for 9:12, to get the real roof area. That area is converted to roofing squares of 100 sq ft each, rounded up; asphalt shingles take 3 bundles per square (about 33.3 sq ft per bundle). Cost is the roof area times a built-in material rate ($4 per sq ft for asphalt shingles, $12 for metal, $15 for tile) plus labor per square ($200, $350 and $400). No waste allowance is added.

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: Asphalt Shingles on a 40 × 30 ft Footprint

  1. 1 Input: a roof footprint of 40 ft by 30 ft including overhangs, a 6:12 pitch and asphalt shingles.
  2. 2 Roof area: 40 × 30 = 1,200 sq ft of footprint × 1.12 = 1,344 sq ft. Squares: 1,344 ÷ 100 = 13.44, rounded up to 14, which is 42 bundles.
  3. 3 Cost: material 1,344 × $4 = $5,376; labor 14 squares × $200 = $2,800; total $8,176.
  4. 4 Waste: the calculator adds none. With 10% for cuts, 1,344 × 1.10 = 1,478 sq ft, or 15 squares (45 bundles). Underlayment, drip edge, flashing and tearing off the old roof are not in the estimate.

Source: HomeAdvisor · Last updated: September 2026

Frequently Asked Questions

How much does a new roof cost?
The calculator's built-in rates are $4 per sq ft of roof for asphalt shingles, $12 for metal and $15 for tile, plus labor of $200, $350 and $400 per square. For 2,000 sq ft of roof (20 squares) that comes to $12,000 for asphalt shingles, $31,000 for metal and $38,000 for tile. Real quotes vary with region, pitch, tear-off and how complex the roof is.
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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