🏠 Roofing Calculator
Calculate roofing squares, shingle bundles, and materials. Accounts for roof pitch.
Quick Formula
Roof Area = Footprint Area × Pitch Factor × 1.10 (waste)
Squares = Roof Area ÷ 100
Pitch Factors
| Pitch | Factor |
|---|---|
| Flat (0:12) | 1.00 |
| 3:12 | 1.03 |
| 4:12 | 1.05 |
| 5:12 | 1.08 |
| 6:12 | 1.12 |
| 7:12 | 1.16 |
| 8:12 | 1.20 |
| 10:12 | 1.30 |
| 12:12 | 1.41 |
Materials Per Square
| Material | Per Square |
|---|---|
| 3-tab shingles | 3 bundles |
| Architectural shingles | 3-4 bundles |
| Underlayment (15#) | 1 roll per 4 squares |
| Starter strip | 1 per 3 squares |
| Ridge cap | Measure ridge length |
| Nails | 2-3 lbs |
Example Calculation
Given: 30' × 40' footprint, 6:12 pitch
- Footprint area: 30 × 40 = 1,200 sq ft
- Apply pitch factor: 1,200 × 1.12 = 1,344 sq ft
- Add 10% waste: 1,344 × 1.10 = 1,478 sq ft
- Convert to squares: 1,478 ÷ 100 = 14.8 squares
Materials needed:
- Shingles: 15 squares × 3 = 45 bundles
- Underlayment: 4 rolls
- Starter: 5 bundles