Roof Replacement Cost Estimator
Planning estimate, not a contractor quote. Roofers price by the square (100 sq ft). Enter your roof and local per-square rate for the range.
Roof Replacement Cost Estimator
About this roof replacement cost estimator
Roof replacement is one of the biggest checks a homeowner writes, and quotes can span a 2× range for the same roof. The anchor is simple: roofing squares × installed cost per square. This estimator computes your squares from roof dimensions and pitch (with waste), then applies your local per-square rate — defaulting to $450, a reasonable 2026 US figure for architectural shingles with tear-off.
What moves a quote off the anchor: pitch (steep roofs need staging and slow crews down), complexity (valleys, dormers, skylights = labor), tear-off layers (two old roofs cost more to remove than one), decking repairs (rotten plywood found mid-job), and material tier (3-tab vs. architectural vs. designer shingles).
Red flags in quotes: a price far below the pack (uninsured crew, no tear-off, vague scope), pressure to sign today, or no mention of underlayment, flashing, and ventilation. A good quote itemizes squares, tear-off, materials tier, and warranty terms.
Worked example: pricing a 30×40 roof
A house with a 30×40 ft footprint has 1,200 square feet of footprint. At a 6/12 pitch, multiply by the pitch factor 1.118: 1,200 × 1.118 = 1,341.6 square feet of actual roof. Add 10% waste for cuts, valleys, and starter courses: 1,475.76 square feet, or 14.76 roofing squares.
At $450 per square installed (mid-range architectural shingles in many markets), the planning estimate is 14.76 × $450 = $6,641. This calculator shows a range around that midpoint: roughly $5,313 on the low end to $8,301 on the high end. The spread reflects real market variation — tear-off difficulty, roof complexity, and regional labor rates move the number more than the shingle brand does.
Getting a useful number
The per-square rate you enter is everything. A plain gable roof with easy access prices very differently from a cut-up roof with dormers, steep pitches, and three layers of tear-off — complexity can double labor time. Get three local quotes and ask each roofer to break out tear-off/disposal, underlayment, shingles, ridge cap, and flashing separately; lump-sum bids hide the padding.
Watch for the extras that bids bury: plywood replacement (often $50–$100 per sheet, and you will not know how many sheets until tear-off), dumpster and permit fees, and upgraded underlayment in ice-dam zones. This is a planning estimate, not a contractor quote — use it to sanity-check bids, not to set your final budget.
How to use
- Enter roof length and width (eave-to-ridge doubled) in feet.
- Select your roof pitch.
- Enter the installed cost per square in your area (default $450).
- Press Calculate, then get 3 itemized local quotes to compare.
Good to know
- Asphalt shingles only — metal, tile, and slate cost 2–4× more.
- Assumes single-layer tear-off; extra layers and decking repairs add cost.
- Planning estimate, not a quote. Regional labor markets swing per-square rates widely.
- Tear-off vs. overlay: laying new shingles over one existing layer saves tear-off and disposal (often $1,000–$2,000) but adds weight and can void some manufacturer warranties — and most codes allow a maximum of two layers.
- Ridge caps, starter strips, underlayment, and flashing are usually 10–15% of material cost — a per-square quote should itemize whether they are included.
Frequently asked questions
How much does it cost to replace a roof?
For asphalt shingles in the US, typical installed cost runs $350–$600+ per square (100 sq ft), putting most homes at $8,000–$18,000+. Steep or complex roofs run higher; get itemized local quotes.
What is a roofing square?
100 square feet of roof coverage. Both materials and labor are commonly quoted per square.
How much does it cost to shingle a 1500 sq ft house?
A 1,500 sq ft footprint at a typical 6/12 pitch works out to about 18.4 squares with waste — at $450/square, expect roughly $6,600–$10,400 for a straightforward asphalt job, more for steep or complex roofs.
Does roof pitch affect replacement cost?
Yes, significantly. Steep roofs (10/12+) need safety staging and slower work, often adding 20–40% to labor versus a walkable 4/12–6/12 roof.
Should I get multiple roofing quotes?
Always get at least three, itemized by squares, tear-off, shingle tier, underlayment, flashing, and warranty. This estimator gives you the anchor to judge them against.
How much does it cost to shingle a 30x40 roof?
A 30×40 ft footprint (1,200 sq ft) at 6/12 pitch is about 1,342 sq ft of roof, or 14.76 squares with 10% waste. At $450 per square, that is roughly $6,641 mid-range, with a planning range of $5,313–$8,301. Enter your dimensions above for your exact numbers.
What is a roofing square?
One roofing square = 100 square feet of roof area. Shingles are sold by the bundle, typically 3 bundles per square for standard architectural shingles. Roofers quote labor per square too, which is why the whole trade thinks in squares.
How does roof pitch affect the cost?
Two ways: steeper roofs have more surface area (a 12/12 pitch has about 41% more area than the same footprint at 4/12), and labor costs climb because crews move slower and need more safety gear above roughly 7/12 pitch. Both effects are captured when you enter the correct pitch above.
What should a per-square roofing quote include?
Tear-off and disposal, underlayment, shingles, ridge cap, flashing, vents, and cleanup. Ask whether plywood replacement (often $50–$100 per sheet) is included or billed extra — it is the most common surprise line item on roofing invoices.