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Roofing Calculator

Calculate the number of shingle bundles needed for your roof based on area and pitch. Accounts for roof slope and waste.

Roof Dimensions

m

Measure the longest dimension of your roof footprint

m

Measure the shortest dimension of your roof footprint

Enter pitch as rise over 300 mm run (e.g., 100 = 4:12 slope)

%

Add 10% for simple gable roofs, 15% for complex roofs with hips and valleys

Roofing Tips

  • •Steeper roofs (8/12+) require more bundles due to increased surface area
  • •Add 10% extra for waste, 15% for complex roofs with valleys
  • •Order in full square (9.3 m²) increments — partial squares are wasted
  • •Don't forget underlayment, drip edge, ridge cap, and starter strips

Ready to Calculate

Enter your roof dimensions to get shingle estimates

Understanding Roof Calculations

Roofing is sold by the 'square' (100 sq ft). Pitch affects total area:

  1. Calculate base area (length Ă— width)
  2. Apply pitch multiplier to account for slope
  3. Divide by 100 to get 'squares'
  4. Multiply by pitch factor to get actual roof surface area
  5. Add 10–15% waste factor and convert to bundles (3 per square)

Common Roof Pitches

  • Low Pitch 2:12 – 4:12, requires special roofing materials
  • Standard Pitch 4:12 – 6:12, most common residential pitch
  • Steep Pitch 7:12 – 12:12, adds complexity and cost

⚠️ Important Notes

  • Prices vary widely by region and material quality
  • Always get at least 3 contractor quotes
  • Permits may be required for full roof replacement