roof area calculator
Roof Area Calculator
Estimate your roof area in square metres — free and fast. As a general guide only for Australian homes.
Step 1 — Select Your Roof Shape
Step 2 — Enter Your Roof Dimensions
m
m
°
Common pitches: 15°, 22°, 30°, 45°
°
m
| Pitch Angle | Rise per 1m Span | Typical Application |
|---|---|---|
| 1° – 4° | < 0.07 m | Flat roof decks, commercial buildings |
| 5° | 0.09 m | Carports, sheds, industrial (NCC min. for steel) |
| 10° | 0.18 m | Verandahs, skillion additions |
| 12° | 0.21 m | NCC minimum for most roof tile products |
| 15° | 0.27 m | Modern homes, extensions |
| 22° – 25° | 0.40 – 0.47 m | Standard Brisbane residential home |
| 30° | 0.58 m | Traditional homes, good drainage |
| 35° | 0.70 m | Heritage homes, Queenslanders |
| 45° | 1.00 m | Decorative gables, heritage |
Minimum pitch requirements are governed by the National Construction Code (NCC) 2022, Volume Two, Section 8 — Roof and Wall Cladding. Always verify product-specific minimums with your roofing manufacturer and a licensed contractor.
Waste / Overlap Factor
Please fill in all required fields.
Your Roof Area Estimate
Total Roof Area
—
m²
Base Footprint
—
m²
Pitch Multiplier
—
factor
Area with Waste
—
m²
Calculation Breakdown
⚠️ This estimate is a guide only and is based on standard geometric calculations. Actual material requirements may vary due to overhangs, valleys, skylights, and installation method. We recommend a professional roof inspection and quote from a licensed roofing contractor before purchasing materials.