Roof Area Calculator for NZ Roofers & Builders
Calculate the actual roof area for quoting, ordering materials, or scoping a roofing job. The key factor is pitch — a steeper roof has significantly more area than the house footprint.
Common NZ Roof Pitches
| Pitch (degrees) | Description | Area multiplier |
|---|---|---|
| 5° | Near flat (skillion/commercial) | 1.004× |
| 15° | Shallow residential | 1.04× |
| 20° | Common NZ residential | 1.06× |
| 25° | Medium pitch | 1.10× |
| 30° | Steep residential | 1.15× |
| 35° | Very steep | 1.22× |
Materials Per m² (NZ)
- Colorsteel/corrugate: ~1.05 m² ordered per 1 m² area (5% lap wastage)
- Concrete/clay tiles: ~10–12 tiles per m² depending on tile size
- Metal tiles: ask supplier for coverage rate
Roof Replacement Costs
See our roof replacement cost guide for Auckland, Wellington, Christchurch and more.