Roof Replacement Cost Calculator
Use this roof replacement cost calculator to estimate what a full tear-off and new roof will cost based on your home's footprint, roof pitch, material, complexity, and region. You get a total with a realistic range, an itemized breakdown, and a side-by-side comparison of every roofing material.
Every 12 inches of horizontal run adds the "rise" shown, so steeper roofs have more surface area than the footprint below them.
How to Use This Roof Replacement Cost Calculator
Enter the footprint of the area covered by your roof, including overhangs, garages and covered porches under the same roofline. Set the pitch slider to your roof's rise per 12 inches (a 6/12 roof rises 6 inches for every 12 inches of horizontal run), then choose a material, complexity level, number of existing layers, and your region. Add the percentage of decking you expect to replace, plus chimneys, skylights and ridge vent.
Press Calculate (or hit Enter) to see your estimated total and range, the real roof surface area in square feet and roofing squares, how much material to order, an itemized cost table, and a comparison of all nine materials for your exact roof.
Why This Matters
A roof replacement is usually the single largest repair bill a homeowner faces. For an average American house it lands between $8,000 and $30,000, and the spread comes from decisions you can plan for: material, pitch, tear-off, and how much of the wood underneath has rotted. Contractors price by the "square" (100 square feet of roof surface), not by the size of your house, so a 2,000 sq ft footprint at a 6/12 pitch is really 22.4 squares, not 20. Skipping that step is why so many homeowners are surprised by a bid.
Use the calculator before you call roofers so you can tell whether a quote is reasonable. It is equally useful when budgeting for a home purchase, preparing for an insurance claim after hail or wind damage, or deciding whether stepping up from architectural shingles to standing-seam metal is worth roughly double the price. A bid that looks $3,000 cheaper often leaves out tear-off, decking, or flashing, and the line-item table shows you exactly what should be in there.
How It's Calculated
The calculator converts your footprint into true roof surface, then prices each part of the job separately:
roof area = footprint × slope factor
squares = roof area ÷ 100
roofing = squares × price per square × region × complexity × (1 + steepness)
Installed prices per square (material plus labor, average region, simple roof) are: 3-tab asphalt $375, architectural asphalt $475, composite $700, exposed-fastener metal $650, standing-seam metal $1,200, cedar shake $950, concrete tile $850, clay tile $1,250, and slate $1,700. Region multiplies everything by 0.88, 1.00, or 1.25. Complexity multiplies roofing by 1.00, 1.12, or 1.28. Steepness adds 0% up to 6/12, 8% up to 9/12, 20% up to 12/12, and 35% above that for roof jacks and fall protection.
Tear-off and disposal costs $95 per square for one layer, $175 for two, and $255 for three or more. Decking is your percentage of roof area, rounded up to whole 4×8 sheets, at $4.25 per sq ft. Add-ons are $400 per chimney, $450 per skylight, and $9 per foot of ridge vent. Permit and inspection fees are the greater of $150 or 1.5% of the subtotal. Contingency applies to the subtotal plus permit, and the final total is rounded up to the next $10. The range shown is −15% to +20% of the total.
Material order quantity adds 10%, 15% or 20% waste for simple, moderate and complex roofs, rounded up to whole bundles (3 per square) for asphalt shingles. Every rounding step errs toward the higher cost.
Worked Example
A 2,000 sq ft footprint, 6/12 pitch, architectural shingles, simple roof, one layer to tear off, average region, 10% decking, one chimney, 40 ft of ridge vent, and 10% contingency (the tool's default inputs):
- Slope factor: √(6² + 12²) ÷ 12 = √180 ÷ 12 = 1.118.
- Roof area: 2,000 × 1.118 = 2,236 sq ft, or 22.36 squares.
- Roofing: 22.36 × $475 = $10,621 (no steepness adjustment at 6/12).
- Tear-off: 22.36 × $95 = $2,124.
- Decking: 10% of 2,236 = 223.6 sq ft, rounded up to 7 sheets (224 sq ft) × $4.25 = $952.
- Add-ons: chimney $400 plus ridge vent 40 ft × $9 = $360.
- Subtotal: $14,457. Permit is 1.5% = $217, giving $14,674. Contingency at 10% is $1,467, for $16,141.
- Total: rounded up to $16,150, with a range of $13,730 to $19,380. That works out to $7.22 per sq ft of roof, about $722 per square.
- Order quantity: 22.36 × 1.10 waste = 24.6 squares, rounded up to 74 bundles (24.67 squares).
In the comparison table the same roof in 3-tab shingles comes to about $13,650, and in standing-seam metal about $34,250.
Tips & Common Mistakes
- Measure the footprint, not the floor area. Include overhangs, an attached garage, and covered porches. Forgetting the garage can understate the roof by 400 sq ft or more.
- Ask for decking priced per sheet. Rot is rarely visible until the old roof is off. A written per-sheet price prevents arguments and surprise change orders.
- Do not roof over a second layer. Model codes (IRC R908) generally require tear-off to the deck where two or more layers exist, and extra layers add weight and hide leaks. This tool always prices a full tear-off.
- Check structure before choosing tile or slate. These weigh roughly 600–1,500 lb per square versus 200–250 lb for asphalt shingles, and many roofs need framing reinforcement.
- Compare line items, not totals. Confirm each quote includes underlayment, drip edge, flashing, ventilation, cleanup and permit. Verify the contractor's license and insurance.
- Keep the contingency. Older homes with unknown deck condition often use all of a 15% allowance.
Frequently Asked Questions
How much does it cost to replace a roof?
For a typical 2,000 sq ft home with architectural asphalt shingles, expect roughly $12,000 to $20,000 including tear-off. Metal runs $20,000 to $40,000, and tile or slate can exceed $40,000. Pitch, complexity and local labor rates shift these numbers considerably.
What is a roofing square?
A square is 100 square feet of roof surface. Contractors quote and order materials in squares, and three bundles of asphalt shingles typically cover one square. A roof of 2,236 sq ft is 22.36 squares.
Is it cheaper to put a new roof over the old one?
An overlay can save the tear-off cost, but it is often not allowed when two layers already exist, it hides deck damage, and it can shorten the new roof's life. This calculator assumes full tear-off so the estimate stays on the safe side.
How much does roof pitch affect the price?
Pitch affects cost in two ways. Steeper roofs have more surface area for the same footprint (a 12/12 roof has 41% more surface than a flat one), and roofs above 6/12 need extra safety equipment and labor time. The calculator adds both effects.
How accurate is this roof cost estimate?
Treat it as a planning figure within about −15% to +20%. Real bids depend on your contractor, material availability, access, deck condition and local permit costs. Use the estimate to sanity-check quotes, then get at least three written bids.
Does homeowners insurance cover roof replacement?
Policies usually cover sudden damage such as hail, wind or fallen trees, but not wear and age. Some pay replacement cost value and others only actual cash value after depreciation, so check your policy and deductible before filing a claim.