←
Roof Pitch Calculator
mm
mm
Roof Pitch Formula
Pitch Angle: atan(Rise / Run) × 180 / π
Rise per Metre: (Rise / Run) × 1000
Ratio: 1 : (Run / Rise)
Rise per Metre: (Rise / Run) × 1000
Ratio: 1 : (Run / Rise)
Roof Pitch Calculator — Angle, Rise & Run
Australia approved 171,000 new dwellings in 2025 (ABS). Correct roof pitch is critical for weatherproofing, structural design, and material selection. Calculate pitch from rise and run: Pitch = arctan(Rise ÷ Run).
Common Australian Roof Pitches
| Pitch | Rise per Metre Run | Typical Use | Suitable Materials |
|---|---|---|---|
| 2–5° | 35–87mm | Flat roofs, skillion | Metal deck, membrane |
| 5–10° | 87–176mm | Low-pitch residential | Colorbond, Klip-Lok |
| 15° | 268mm | Standard residential | Metal, flat concrete tiles |
| 20° | 364mm | Min. for concrete tiles | Concrete tiles, metal |
| 22.5° | 414mm | Most common AU pitch | All materials |
| 25° | 466mm | Traditional residential | All materials |
| 30° | 577mm | Steep pitch / loft space | All materials, slate |
| 35–45° | 700–1000mm | Heritage, alpine areas | Slate, shingles, metal |
Minimum Pitch Requirements (AS 1562 / NCC)
| Roofing Material | Minimum Pitch |
|---|---|
| Metal sheeting (Colorbond) | 1–2° (profile dependent) |
| Concrete roof tiles | 20° |
| Terracotta tiles | 20° |
| Fibre cement (flat) | 5° |
| Slate | 25° |
Tips for Roof Pitch Selection
- Check your local council and NCC requirements for minimum pitch.
- Steeper pitches shed water faster but cost more in materials and framing.
- Low-pitch roofs (<10°) need sarking for condensation management.
- Wind ratings affect pitch choice — consult AS 4055 for your wind region.
More than just calculators
Built Simple manages your entire project — estimates, schedules, tasks, and team.