CostCandor

Roof replacement cost calculator

Enter your home's footprint, roof pitch, and material. You get a low / typical / high installed-cost range — and the worksheet we used to get there, so you can challenge any assumption.

Last reviewed 2026-07-04 · pricing data as of 2026-06 · how we build these numbers

Ground-floor area under roof — not total living area of a multi-story home.
Steeper roofs have more surface and cost more per square foot to work on.
Installed cost per square (100 sq ft), labor included.
Old roof removal Most re-roofs require removing the old layer. Uncheck only for new construction.

How this estimate is built

The calculator does exactly four things, in the open:

  1. Roof area. Your footprint is multiplied by a pitch factor (1.02 for flat up to 1.42 for steep) to approximate the true sloped surface, then divided by 100 to get roofing "squares" — the unit contractors actually price in.
  2. Waste factor. Squares are increased 10% for cut-offs, ridge caps, and starter strips. Complex roofs with many valleys can run higher; simple gable roofs a bit lower.
  3. Material rate. Each material carries a low / typical / high installed cost per square — labor, underlayment, flashing, permit, and disposal included — from the sources listed below.
  4. Tear-off. If the old roof comes off, removal and dump fees are added per square of actual roof area.

Data sources

Pricing seed data: BLS Producer Price Index (roofing contractors), national retail material pricing, and 2025–2026 contractor cost surveys. See methodology for the full trail and pull dates.

What can move your real price outside this range

  • Roof complexity — hips, valleys, dormers, and skylights add labor and waste beyond the flat 10% factor.
  • Regional labor — coastal metros commonly run 15–30% above the national typical band; rural markets below it.
  • Decking repairs — rotted sheathing is only discovered after tear-off; prudent budgets hold 10% in reserve.
  • Multiple existing layers — removing two or three old layers costs more than the single-layer tear-off priced here.

Frequently asked questions

Why do you ask for footprint, not roof area?

Almost nobody knows their true sloped roof area, but county records and listing sites give the ground footprint. The pitch factor converts one to the other — and unlike sites that just guess, we show the factor we used so you can correct it.

Is this a quote?

No. It's a planning range built from published data, meant to tell you whether a real bid is in reasonable territory. Get at least three written quotes; our quote checklist shows what each one must itemize.

Which band should I budget on?

Budget the typical band plus a 10% contingency. If every local bid lands near or above our high band, your market or roof complexity is above average — ask bidders to walk you through their squares and pitch numbers.