Roofing Calculator
Figure out exactly how many shingles, bundles, and rolls of underlayment you need — plus total cost. Pitch factor handled automatically.
Last updated: February 8, 2026
Enter Roof Details
Remove old shingles and install new — most common
Roof Footprint
Measure the outside edges of your house at ground level. Include roof overhangs if possible.
Most common US roof pitch — balanced look (27° · factor ×1.118)
Most popular — textured, thicker, wind-resistant · 30-50 years warranty
% (10-15% typical)
Use 15% for complex roofs with hips, valleys, or dormers.
Results
Roofing Squares Needed
15
13.42 squares + 10% waste
1 square = 100 sq ft · Architectural (Dimensional)
Footprint Area1,200 sq ft
Pitch Factor (6/12)×1.118
Actual Roof Area1,341.6 sq ft
Materials Needed
Shingle Bundles: 45 bundles
Underlayment: 4 rolls
Drip Edge: 148 ft
Ridge Cap: 2 bundles
Roofing Nails: 26.3 lbs
Cost Estimate
Materials:$2,250
Labor:$5,250
Tear-Off:$1,875
TOTAL: $9,375
*Estimate only. Actual costs vary by region, roof complexity, and contractor.
Shopping Tips
- • 45 bundles at ~70 lbs each = ~3,150 lbs total — schedule delivery
- • Architectural shingles are the most popular choice — good balance of cost, look, and durability
- • Factor in dumpster rental ($300-500) for old shingle disposal
- • Order all materials at once — shingle colors can vary between production runs
How to Use This Calculator
- Choose your project type — New roof, reroof (tear-off), roof-over, or repair. Reroof includes tear-off cost in the estimate.
- Enter your roof footprint — Measure the length and width of your house at ground level. The calculator adjusts for pitch automatically.
- Select your roof pitch — If you don't know it, measure from inside the attic: hold a level out 12 inches and measure the rise. Common residential pitches are 4/12 to 8/12.
- Pick your shingle type — 3-tab is cheapest, architectural is most popular, premium gives a luxury look, and metal lasts the longest.
- Review your shopping list — Shingles, underlayment, drip edge, ridge cap, nails — everything in one place. Copy it to share with your contractor or take to the store.
How We Calculate
Roof Area = Footprint Area × Pitch Factor
Squares = Roof Area ÷ 100 | Bundles = Squares × 3 (standard)
Pitch Factors
- • 4/12: ×1.054 — easy to walk, common
- • 6/12: ×1.118 — most popular US pitch
- • 8/12: ×1.202 — moderate, good drainage
- • 12/12: ×1.414 — 45° angle, maximum
Material Estimates
- • Shingles: 3 bundles per square
- • Underlayment: 1 roll per 4 squares
- • Ridge cap: 33 lin ft per bundle
- • Nails: ~1.75 lbs per square
Example: 40×30 ft Roof with 6/12 Pitch
- Footprint: 40 × 30 = 1,200 sq ft
- Pitch factor (6/12): ×1.118
- Actual roof area: 1,200 × 1.118 = 1,342 sq ft
- Roofing squares: 1,342 ÷ 100 = 13.4 squares
- With 10% waste: 13.4 × 1.1 = 15 squares
- Bundles (architectural): 15 × 3 = 45 bundles
2026 Roofing Cost Guide
- 3-Tab Shingles: $80-120/square material, $250-350/square installed — budget option, 20-25 year life.
- Architectural: $120-200/square material, $350-500/square installed — best value, 30-50 year warranty.
- Premium: $250-400/square material, $500-800/square installed — luxury look, lifetime warranty.
- Metal: $350-600/square material, $600-1,200/square installed — 40-70 year life, energy savings.
Calculations based on NRCA (National Roofing Contractors Association) Roofing Manual and ARMA shingle standards. Learn more