How do I estimate roof area?

If you don’t have pitch-adjusted area, multiply footprint by a pitch factor or use a measuring app. Adjust up for hips/valleys.

What waste percentage should I use?

10–15% is common; complex roofs may need more. Start at 12–15% for hips/valleys.

Does this include plywood replacement?

No. Add a separate allowance if you expect decking repairs.

Set tear-off to No for overlays to remove removal/disposal cost. Full tear-off is recommended if existing shingles are failing.

Does it price metal or tile?

Use your material/labor per square for those systems; this model is per-square and works with any per-square pricing.

construction calculator

Roof Replacement Cost Calculator

Estimate roof replacement cost with material, labor, tear-off, and waste allowance.

Results

Adjusted area (sq ft): 2420.00
Squares (100 sq ft units): 24.20
Material cost: $2,662
Labor cost: $6,050
Tear-off/disposal: $1,815
Estimated total cost: $11,027
Cost per sq ft: $5

How to use this calculator

Enter roof area (sq ft) and waste percentage.
Enter material cost/sq, labor/sq, and tear-off/disposal per sq.
Toggle tear-off on/off to model overlay vs full replacement. Review total and cost per sq ft.

Inputs explained

Roof area: Use pitch-adjusted area if known; otherwise footprint × pitch factor.
Material cost per square: Shingles or chosen material per 100 sq ft including underlayment if bundled.
Labor cost per square: Install labor per 100 sq ft.
Tear-off/disposal per square: Removal and dump fees per 100 sq ft (set to 0 for overlays).
Waste allowance: Extra for starter, ridge/hip, and cut waste (10–15% common).
Include tear-off: Turn off for overlays; on for full replacements.

How it works

Squares = (Roof area × (1 + waste)) ÷ 100. Costs per square are multiplied by squares.

Material + labor + optional tear-off/disposal = total. Cost per sq ft = total ÷ roof area.

Formula

Adjusted area = Roof area × (1 + Waste%)
Squares = Adjusted area ÷ 100
Material cost = Squares × Material $/sq
Labor cost = Squares × Labor $/sq
Tear-off cost = Squares × Tear-off $/sq (if applied)
Total = Material + Labor + Tear-off
Cost per sq ft = Total ÷ Roof area

When to use it

Budgeting a reroof before collecting bids.
Comparing overlays vs full tear-off scenarios.
Testing how material upgrades or higher waste percentages impact total cost.

Tips & cautions

Steeper roofs and complex shapes need higher waste allowances; start at 12–15% for hips/valleys.
Include underlayment, ice/water shield, flashing, and ventilation in material if not priced separately.
Local dump fees and plywood replacement can add costs—adjust tear-off or add a buffer as needed.
Does not price decking replacement, ventilation upgrades, or specialty materials (metal, tile) explicitly.
Assumes per-square pricing; line-item extras may vary by contractor.
Waste is a single percentage; complex roofs may require section-by-section estimates.

Worked examples

2,200 sq ft roof, 10% waste, $110 material/sq, $250 labor/sq, $75 tear-off/sq

Adjusted area ≈ 2,420 sq ft; Squares ≈ 24.2
Material ≈ $2,662
Labor ≈ $6,050
Tear-off ≈ $1,815
Total ≈ $10,527; Cost/sq ft ≈ $4.78

1,800 sq ft roof overlay, 12% waste, $140 material/sq, $275 labor/sq, no tear-off

Adjusted area ≈ 2,016 sq ft; Squares ≈ 20.16
Material ≈ $2,822
Labor ≈ $5,544
Tear-off = $0 (overlay)
Total ≈ $8,366; Cost/sq ft ≈ $4.65

Deep dive

This roof replacement cost calculator multiplies your roof area (with waste) by material, labor, and optional tear-off costs to show total cost and cost per square foot.

Use it to compare overlay vs tear-off and see how changes in waste allowance or material pricing affect your roofing budget.

FAQs

How do I estimate roof area?: If you don’t have pitch-adjusted area, multiply footprint by a pitch factor or use a measuring app. Adjust up for hips/valleys.
What waste percentage should I use?: 10–15% is common; complex roofs may need more. Start at 12–15% for hips/valleys.
Does this include plywood replacement?: No. Add a separate allowance if you expect decking repairs.
Overlay vs tear-off?: Set tear-off to No for overlays to remove removal/disposal cost. Full tear-off is recommended if existing shingles are failing.
Does it price metal or tile?: Use your material/labor per square for those systems; this model is per-square and works with any per-square pricing.

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Estimates only. Roofing costs vary by region, roof complexity, and material choice. Confirm with a roofing professional before contracting.