Repairs & renovations

Roof Replacement Cost Calculator

Create an editable roof estimate from plan dimensions, pitch, waste, materials and labour.

What this calculator estimates

Estimate roofing material and installation cost. It combines the inputs below to produce Estimated roof cost. Every assumption remains editable so the estimate can reflect the property, financing and location being evaluated.

Worked example

Using the displayed sample assumptions, the calculator produces $17,372. This is an illustration, not a market quote. Change one input at a time to understand what drives the result.

Inputs and assumptions

• Building length — sample input: 40 ft
• Building width — sample input: 30 ft
• Roof pitch multiplier — sample input: 1.12 factor
• Waste allowance — sample input: 10 %
• Material cost per sq. ft. — sample input: 4.5 currency units per sq. ft.
• Labour cost per sq. ft. — sample input: 5 currency units per sq. ft.
• Tear-off and disposal — optional — sample input: 2500 currency units
• Permits or extras — optional — sample input: 0 currency units
• Sales tax — optional — sample input: 5 %

How to interpret the result

Replace sample unit prices with current local quotes. Compare a conservative case with an expected case and keep a record of the assumptions used.

Common mistake to avoid

Do not omit demolition, permits, tax, delivery or contingency. Local definitions, taxes, lending practices and measurement requirements can materially change the result.

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Reviewed 2026-09-08.