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Free tools › Contractors › Roof replacement cost calculator

Free calculator · no sign-up

Roof replacement cost calculator

Estimate roof area from the house footprint and pitch, add waste, and price the job from your own rate per square.

✓ Free✓ Works on your phone✓ Any tax rate

The roof

Roofing squares (with waste)
Footprint
Pitch factor
Roof surface
Shingle bundles (3 per square)
Install
Tear-off
Extras
Tax
Total
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How it’s calculated

  • Pitch factor = √(1 + (rise ÷ 12)²). A 6/12 roof has 1.118 times the area of its footprint.
  • Roof surface = footprint × pitch factor. Squares = surface × (1 + waste %) ÷ 100.
  • Most architectural shingles come 3 bundles to a square — check your product.
  • Always measure on site; dormers, multiple levels and steep pitches change the numbers.

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Questions

What is a roofing square?

100 square feet of roof surface.

Why add waste?

Cuts at hips, valleys, rakes and starter courses use extra material — usually 10–15%.