Roofing Calculator
Calculate roofing materials, shingles needed, and roofing costs. Free, fast, accurate — no signup, mobile-friendly, work
Roof Specifications
Common: 4/12, 6/12, 8/12
Base Roof Area
1200 sq ft
Before pitch adjustment
Roofing Requirements
Total Project Cost
$6,587
$464/square
Roofing Squares
14.2
100 sq ft each
Net Roof Area
1290 sq ft
After pitch & openings
Cost Breakdown
Materials:$2,128
Labor:$1,383
Additional:$3,076
Total:$6,587
Project Timeline
Underlayment Installation
Install protective barrier
1 days
Material Installation
Install Asphalt Shingles
1 days
Finishing Work
Ridge vents, flashing, gutters, cleanup
1-2 days
Roofing Tips
- • Schedule roofing work during dry, mild weather
- • Ensure proper ventilation to prevent ice dams
- • Check local building codes for material requirements
- • Consider energy-efficient materials for tax credits
- • Plan for proper disposal of old roofing materials
How it works
A roofing calculator estimates material from the roof area, measured in “squares” (one square = 100 square feet). Because roofs are pitched, the actual surface is larger than the building footprint, so a slope factor is applied.
Roofing squares
Roof area = footprint × slope factor Squares = roof area ÷ 100
- footprint
- ground area under the roof
- slope factor
- 1.05 (low) to 1.25+ (steep)
Worked example
- Footprint = 2,000 ft²
- Moderate pitch → slope factor 1.12
- Roof area = 2,000 × 1.12 = 2,240 ft²
- Squares = 2,240 ÷ 100
≈ 22.4 squares — order ~24 to cover waste and starter/ridge rows.
Good to know
- Steeper roofs have a bigger slope factor, so the same footprint needs more material.
- Add 10–15% for waste, plus extra for hips, valleys, and ridge caps.
- Three bundles of standard asphalt shingles typically cover one square.