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Roofing Calculator

Squares, bundles, underlayment, and total cost for your roof replacement. Plus a 50-year lifespan comparison across 7 materials.

Estimated total
$8,001–$13,474
Squares
18.45 · Architectural
Project details
Roof footprint
Section 1
Footprint: 1500 sq ftRoof area: 1677 sq ft
Total roof area1677 sq ft · 16.77 squares
Roofing material
Architectural Shingles — Standard residential choice. Better look, longer lifespan than 3-tab. 25–30 yr.

Optional override

Tear-off & decking

Older roofs may have 2-3 layers

$50–$100/sheet (4×8 = 32 sq ft)

Underlayment & flashing

Auto: 80 lf (half perimeter for eaves)

0 if no valleys (simple gable)

Penetrations

$40–$80 each

$200–$500 each

$200–$400 each

Permits & labor

Cost breakdown

Itemized for your selected configuration.
Architectural Shingles · 18.45 squares × $125/sq$1,845 – $2,767
Underlayment · 5 rolls$125 – $300
Ice & water shield · 80 lf$120 – $280
Drip edge · 160 lf$240 – $480
Ridge cap · 50 lf$100 – $250
Ridge vent · 50 lf$400 – $750
Penetrations · 4 vents + 0 skylights + 1 chimney$360 – $720
Tear-off · 16.77 sq × 1 layer$1,677 – $2,516
Building permit$200 – $800
Pro labor · 16.77 sq × $175–$275/sq$2,935 – $4,612
Total project cost$8,001 – $13,474

50-year cost of ownership

Your same roof across all 7 materials, accounting for replacement cycles.
MaterialOne installLifespanRe-roofs50-yr total
3-tab$9,95018 yr3×$29,849
ArchitecturalYOUR PICK$10,73828 yr2×$21,476
Corrugated metal$18,32645 yr2×$36,653
Standing seam$24,11260 yr1×$24,112
Tile$25,95775 yr1×$25,957
Slate$37,696125 yr1×$37,696
EPDM$11,39225 yr2×$22,784
💡 Asphalt looks cheapest until you factor in 2–3 replacement cycles. Metal and slate often win over 50 years.

Shopping list

Major roofing materials.
  • Architectural Shingles (56 bundles)18.45 squares
  • Synthetic underlayment rolls5
  • Ice & water shield80 lf
  • Drip edge (10' lengths)16 pieces
  • Ridge cap shingles or coil50 lf
  • Ridge vent (4' sections)13 pieces
  • Pipe & vent flashings4
  • Step & counter flashing20 lf
  • Roofing nails (1.25" galvanized)84 lbs
  • Roofing cement (10 oz tubes)4 tubes
  • Roofing shovel & tarps for tear-offSet
  • Safety harness, ladder, knee padsSet
  • Dumpster rental (10–20 yard)1
Get quotes
Get 3+ itemized quotes from licensed, insured roofing contractors in your area.
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How to use this calculator

Measure your home's footprint at ground level (length × width) and enter the roof pitch. The calculator applies the pitch multiplier to get the actual roof area, then accounts for complexity-based waste, tear-off, underlayment, drip edge, ridge cap, and labor.

For complex roofs with multiple sections at different pitches, use the "+ Add roof section" option to enter each separately and the calculator will sum everything.

Pro tips

Don't skip tear-off. Roofing over an existing layer voids manufacturer warranties, hides damaged decking, adds weight, and reduces lifespan. Tear-off is $100–$150 per square — worth it.

Architectural beats 3-tab. The cost difference is small ($10–$30 per square) but architectural shingles last 10+ years longer and look much better. 3-tab is essentially obsolete for primary homes.

Metal pays back over 50 years. Standing seam metal costs 3–5× upfront but lasts 3× longer than asphalt with no maintenance. The 50-year cost comparison usually shows metal as cheaper than 2 asphalt re-roofs.

Get 3 quotes. Roofing labor pricing varies 30–50% between contractors. Get itemized quotes — a low total often hides skipped underlayment or missing flashing. Match exact specs across all bids.

Frequently asked questions

What's a roofing square?▾
A roofing square is 100 square feet of roof area. Materials and labor are typically priced per square. A typical home roof is 20–30 squares (2,000–3,000 sq ft of roof).
How do I figure out my roof pitch?▾
Roof pitch is the rise over a 12-inch run. A 6/12 pitch rises 6 inches every 12 inches horizontally. You can measure with a level and ruler from the underside of the rafters, or use a phone level app placed against the roof slope. 4/12 to 8/12 is typical residential.
How much does a new roof cost?▾
For a typical 2,500 sq ft home (about 25 squares of roof) with architectural asphalt shingles: $7,500–$15,000 including labor and tear-off. Metal: $15,000–$25,000. Slate: $25,000–$60,000+. The calculator shows your specific roof's pricing.
How many bundles of shingles in a square?▾
Asphalt shingles: 3 bundles per square (with some 4-bundle product lines). One bundle covers about 33 sq ft. The calculator uses 3 bundles per square as the default and adjusts based on your waste factor.
Should I tear off the old roof or roof-over?▾
Always tear off. Roofing over voids most manufacturer warranties, can hide damaged decking that should be replaced, adds 5–7 lbs/sq ft of weight (which can exceed structural capacity), and reduces the new roof's lifespan by 25%+.
How long does a roof replacement take?▾
Asphalt on an average home: 1–2 days. Metal: 2–4 days. Tile or slate: 1–2 weeks. Add 1 day for complex roofs, multiple stories, or damaged decking. The crew typically arrives early; expect dust, debris, and noise.
When should I replace my roof?▾
3-tab asphalt: 15–20 years. Architectural asphalt: 25–30 years. Metal: 40–70 years. Tile: 50–100 years. Slate: 75–200 years. Signs you need replacement: granules in gutters, curling/missing shingles, leaks, daylight visible from attic, sagging.
Disclaimer. This calculator provides estimates for planning purposes. Actual roofing costs vary significantly by region, complexity, decking condition, and contractor pricing. Always get multiple quotes from licensed, insured roofing contractors and verify your local code requirements.