Free Calculator

Roofing Calculator

A 2,000 sq ft footprint home at 6:12 pitch needs ~25 squares of roofing = 75 bundles of architectural asphalt shingles. Enter your dimensions for an exact estimate.

Inputs

Look up footprint on county tax records or measure roof from above

Estimate

  • Total roof surface (with 10% waste)
    2214 sq ft
  • Roofing squares (100 sq ft)
    Roofing is sold by the square (100 sq ft). 1 square = 3 bundles of shingles.
    22.14squares
  • Shingle bundles (asphalt)
    3 bundles of asphalt shingles cover 1 square.
    67bundles
  • Underlayment rolls (4 sq each)
    Each 4-square roll covers 400 sq ft of roof.
    6rolls
  • Material cost — low
    $7,748
  • Material cost — high
    $12,175
Estimates use industry-standard formulas. Verify with your contractor before ordering.

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How to calculate roofing materials

Roofing is measured in 'squares' — 1 square = 100 sq ft of roof surface. To calculate roof surface, multiply the home's footprint (top-down area) by a pitch multiplier that accounts for the slope. Add 10% waste for cuts, hips, and valleys.

Pitch is expressed as rise over 12 inches of run. A 6:12 pitch means the roof rises 6 inches for every 12 inches of horizontal distance. Standard pitch multipliers: flat = 1.00, 4:12 = 1.054, 6:12 = 1.118, 8:12 = 1.202, 12:12 = 1.414.

Each square needs 3 bundles of asphalt shingles. Underlayment (synthetic or felt) is sold in 4-square rolls. A typical 2,000 sq ft footprint home at 6:12 pitch needs roughly 24 squares = 72 bundles of shingles + 6 rolls of underlayment.

Formulas used

  • Roof surface
    footprint × pitch_multiplier × 1.10
    Footprint is the top-down area. Pitch multiplier accounts for slope. 10% waste is industry standard.
  • Squares
    roof_surface / 100
    1 square = 100 sq ft. Roofing is sold by the square.
  • Shingle bundles
    squares × 3
    3 bundles of asphalt shingles cover 1 square.

Frequently asked questions

How many shingle bundles do I need for a 2,000 sq ft house?+

A 2,000 sq ft footprint home with a typical 6:12 pitch has about 2,460 sq ft of roof surface = ~25 squares with 10% waste = 75 bundles of asphalt shingles.

How do I figure out my roof pitch?+

Hold a level horizontally against the roof slope. Measure how many inches it rises over 12 inches of horizontal distance. A roof that rises 6 inches over 12 inches is a 6:12 pitch.

How much does a new roof cost in 2026?+

Asphalt 3-tab: $350–$550 per square (materials). Architectural shingles: $450–$700 per square. Metal standing seam: $800–$1,400 per square. Tile: $1,000–$2,000. Slate: $1,500–$3,000. A typical 25-square asphalt re-roof costs $8,500–$13,500 installed.

How many squares are in a roof?+

Divide your total roof surface in square feet by 100 to get squares. A 2,500 sq ft roof = 25 squares. Most residential roofs are 18–35 squares.

How long does an asphalt roof last?+

3-tab asphalt: 15–20 years. Architectural (dimensional) asphalt: 25–30 years. Metal: 40–70 years. Tile and slate: 50–100+ years. Climate, ventilation, and installation quality affect actual lifespan.

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