Roof Replacement Cost Calculator

Building length (footprint)

Building width (footprint)

Eave and rake overhang

Added on every side; 1 ft is typical, 0 if you measured the roof itself.

Pitch (rise per 12 in)

A "6/12 roof" rises 6 in per foot. See the roof pitch calculator.

Height

Roof complexity

Layers to tear off

Your local prices. The defaults below are placeholders that show the arithmetic — replace them with a supplier quote per square and two or three itemised roofing bids. Prices per square differ several-fold between 3-tab shingles, architectural shingles, metal and tile.

Roofing material ($ per square)

Architectural shingles as the placeholder. One square = 100 sq ft.

Underlayment, ice shield, starter, ridge cap, nails ($ per square)

Tear-off and disposal ($ per square per layer)

Installation labour ($ per square)

For a one-storey simple roof; the factors above scale it.

Flashing, drip edge, vents, pipe boots ($)

Permit and inspection ($)

Decking sheets to replace

Allowance for rotten plywood found after tear-off.

Per sheet, installed ($)

Contingency (%)