Estimate what a new roof will cost. Enter your house footprint and roof pitch, pick a roofing material, and set how many old layers come off. You get the roof area in squares and a low-to-high installed cost range, compared across common materials.
Last updated:
Roof size
Measure by
ft
ft
ft
Added on every side.
sq ft
Area the roof covers seen from above, including garage, porches and overhangs.
Rise in inches per 12 in of run.
Material & removal
$/square
$/square
%
Rotten or soft sheathing found during tear-off.
$/sq/layer
$/sq/layer
Removal and disposal per square, per layer.
$/sheet
$
Enter your values to see the result.
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How to use the Roof Replacement Cost Calculator
Enter the roof size as house length and width plus overhang, or as the footprint area seen from above.
Pick the pitch and shape: steeper and more cut-up roofs cost more to install and waste more material.
Choose the roofing material or enter your own installed price per square.
Set tear-off and extras: old layers to remove, decking to replace and permit fees.
Read the range and compare other materials, lifespans and cost per year in the table.
How the roof replacement estimate works
Footprint: (length + 2 × overhang) × (width + 2 × overhang). A 50 × 32 ft house with 1 ft overhangs covers 52 × 34 = 1,768 sq ft.
Roof area = footprint × pitch multiplier. For a 6/12 roof, √(1 + 0.5²) = 1.118, so 1,768 × 1.118 = 1,977 sq ft or 19.8 squares.
Tear-off = squares × number of layers × removal rate. Disposal and dumpster fees are usually included in this rate.
Extras: replacement decking (sheets of 32 sq ft) and permit fees.
The calculator prices the measured squares. The waste allowance (10–20%) is shown separately as the amount to order, because installed prices per square already cover normal waste.
Pitch multipliers
Pitch
Angle
Multiplier
Roof area for 2,000 sq ft footprint
3/12
14.0°
1.031
2,062 sq ft
4/12
18.4°
1.054
2,108 sq ft
5/12
22.6°
1.083
2,167 sq ft
6/12
26.6°
1.118
2,236 sq ft
8/12
33.7°
1.202
2,404 sq ft
10/12
39.8°
1.302
2,603 sq ft
12/12
45.0°
1.414
2,828 sq ft
What drives the price up
Height and access: two- and three-story homes, steep driveways and landscaping that blocks dumpster placement add labor.
Penetrations: every chimney, skylight, vent and valley needs flashing and careful cutting.
Hidden damage: soft or rotten decking is only found after tear-off. Ask contractors for their per-sheet replacement price in the contract.
Code upgrades: ice-and-water shield, drip edge and ventilation may be required by your local code when you reroof.
Season and demand: after big storms, prices and wait times rise. Get at least three written quotes.
Prices in this tool are rough 2025–2026 US reference ranges, not quotes. Edit them to match local bids.
Frequently asked questions
How do I calculate roof replacement cost?
Find the roof area: footprint × pitch multiplier, where the multiplier is √(1 + (pitch ÷ 12)²). Divide by 100 to get roofing squares. Multiply squares by the installed price per square for your material, then add tear-off (squares × layers × removal rate), replacement decking and permit fees. Complex or steep roofs cost more per square.
What is a roofing square?
A square is 100 square feet of roof surface. Roofers price and order materials by the square. A 1,900 sq ft footprint with a 6/12 pitch has about 1,900 × 1.118 = 2,124 sq ft of roof, or 21.2 squares.
How much does a new roof cost per square?
As a rough 2025–2026 US guide, architectural asphalt shingles are often around $450–$700 per square installed, standing-seam metal around $1,000–$1,600, and clay tile or slate considerably more. Prices vary by region, roof height, access and season, so treat the defaults as a starting point and use local quotes.
Can I put new shingles over the old ones?
Many US building codes allow at most two layers of asphalt shingles, and only if the existing roof is flat and sound. An overlay skips tear-off costs, but it hides decking problems, adds weight and can shorten the new roof's life. Choose None in the tear-off setting to price an overlay.
Why does pitch change the price so much?
A steeper roof has more surface area for the same footprint, and on roofs of about 8/12 and steeper, crews need harnesses, roof jacks and more time. The calculator adds a steep-slope factor of 10% at 8/12, 20% at 10/12 and 30% above 12/12 as an assumption; contractors set their own charges.
Does the estimate include gutters, skylights or chimney work?
No. Gutters, skylight replacement, chimney flashing rebuilds, ventilation upgrades and structural repairs are usually priced separately. The complexity setting covers the extra labor for working around these features, not replacing them.
Which roofing material lasts longest?
Natural slate and clay tile can last many decades, often 50 to 100 years or more, while standing-seam metal commonly lasts 40 to 70 years and architectural asphalt about 25 to 30. The table divides each material's midpoint cost by its typical lifespan to show the cost per year of service.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.