Roofing Cost Calculator
Estimate roofing replacement cost by square footage, material, and pitch. Asphalt, metal, and tile. Quote PDF available with Pro.
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What this roofing estimate covers
It turns a roof area and a few site conditions into a planning range for a full replacement, broken into materials, labour, and tear-off. The goal is not to produce a bid — it is to give you a defensible ballpark before you start collecting quotes, so you can tell a fair quote from an inflated one. The estimate responds to the factors that actually move roofing prices: material choice, how tall the building is, how steep the roof is, whether the old roof is stripped off, and how cut up the roof line is.
How the estimate is built
- Squares: roof area ÷ 100. Roofing is priced per “square” (100 sq ft), so 1,800 sq ft is 18 squares.
- Materials are charged per square at the low and high rate for the chosen product, and are not multiplied by pitch or height.
- Labour is charged per square and then multiplied by the story factor (1.00, 1.15, or 1.30), the pitch factor (1.20 for steep), and a 1.20 complexity factor for cut-up roofs.
- Tear-off adds $50–$100 per square when the old roof is stripped to the deck, and nothing for a layover.
A worked example
A 1,800 sq ft two-storey home with asphalt shingles, standard pitch, a simple roof line, and a full tear-off:
| Component | Calculation | Range |
|---|---|---|
| Materials | 18 squares × $100–$200 | $1,800 – $3,600 |
| Labour | 18 × $150–$250 × 1.15 | $3,105 – $5,175 |
| Tear-off | 18 squares × $50–$100 | $900 – $1,800 |
| Total | $5,805 – $10,575 | |
| Cost per sq ft | total ÷ 1,800 | $3.23 – $5.88 |
Material cost ranges used
These are installed-market ranges in US dollars per square, split into material and labour. They vary by region and season.
| Material | Material / square | Labour / square |
|---|---|---|
| Asphalt shingles | $100 – $200 | $150 – $250 |
| Metal | $300 – $700 | $250 – $400 |
| Concrete / clay tile | $400 – $700 | $300 – $500 |
| Cedar shake | $250 – $400 | $250 – $450 |
What moves a real quote beyond this range
- Deck condition. Rotted sheathing, or a second layer to remove, adds both material and disposal cost.
- Underlayment, flashing, and ventilation, which are usually quoted as separate line items.
- Access. No driveway for the dumpster, tight lots, or fragile landscaping all push labour up.
- Regional labour rates, which can differ by 30% or more between markets.
- Season and demand: storm season and peak summer often carry a premium.
Common mistakes
- Using the home’s floor area as roof area. A roof is larger than the footprint on sloped roofs; measure the roof surface or ask for its square count.
- Choosing a layover to save money. It is cheaper now, but it hides deck problems and can shorten the life of the new roof.
- Comparing only the total. Line-item quotes reveal whether underlayment, flashing, and disposal are included or added later.
- Assuming the lowest quote is best. The cheapest bid often omits ice-and-water shield, proper ventilation, or permits.
Frequently asked questions
How do I find my roof’s square footage?
Multiply the footprint by a pitch factor, or ask a roofer for the square count from their measurement. If you know the roof pitch, the roof pitch calculator converts footprint to true surface area.
Is a layover ever a good idea?
Only where building codes allow it, the existing shingles are flat and sound, and you accept a shorter service life. Most roofing advice favours a full tear-off so the deck can be inspected and repaired.
How long does a roof replacement take?
A typical single-family asphalt roof is one to three days of work; larger or more complex roofs, and tile or metal, take longer. Weather and permitting can add time on either side.
Why is a steep roof so much more expensive?
Safety and speed. Steep pitches require more fall protection and slow the crew down, so labour rises — the calculator applies a 20% pitch multiplier for roofs of 10/12 and above.
If you are pricing a whole exterior project rather than just the roof, the same logic applies to cladding: a siding cost estimate responds to area, material, and access in much the same way.