Buyer Tools · Roof Design
Roof Pitch Calculator
Convert roof rise and run into pitch, angle, slope percentage, and approximate rafter length. Use the calculator to compare common roof slopes and better understand your steel building design.
This calculator provides planning estimates only. Final roof design, loading, dimensions, and structural requirements must be confirmed by the building manufacturer and a qualified engineer.
Calculate Roof Pitch From Rise and Run
Accepts decimals and fractions (e.g. 6, 6.5, 6 1/4).
Accepts decimals and fractions (e.g. 6, 6.5, 6 1/4).
Around 4:12–5:12 — a versatile pitch for many steel buildings.
Common Roof Pitch Reference
| Pitch | Angle | Slope % | Rise per 12" | Description |
|---|---|---|---|---|
| 1:12 | 4.76° | 8.33% | 1" | Low slope |
| 2:12 | 9.46° | 16.67% | 2" | Low slope |
| 3:12 | 14.04° | 25.00% | 3" | Low slope |
| 4:12 | 18.43° | 33.33% | 4" | Moderate slope |
| 5:12 | 22.62° | 41.67% | 5" | Moderate slope |
| 6:12 | 26.57° | 50.00% | 6" | Moderate slope |
| 7:12 | 30.26° | 58.33% | 7" | Moderate to steep slope |
| 8:12 | 33.69° | 66.67% | 8" | Moderate to steep slope |
| 9:12 | 36.87° | 75.00% | 9" | Moderate to steep slope |
| 10:12 | 39.81° | 83.33% | 10" | Moderate to steep slope |
| 12:12 | 45.00° | 100.00% | 12" | Steep slope |
What Roof Pitch Means for a Steel Building
Roof pitch influences much more than appearance. On a pre-engineered steel building it can affect:
- Interior clearance and eave/ridge heights
- Water and snow drainage performance
- Roof-panel selection and seam type
- Structural framing and material quantities
- Permitting and code requirements
- Overall project cost
Confirm wind load, snow load, drainage, panel requirements, and structural design with the manufacturer and a qualified engineer for your site.
Planning a Steel Building?
Use your roof-pitch results as a starting point, then let Iron Forge Buildings help you evaluate the full building design, dimensions, engineering requirements, and project goals.
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Frequently Asked Questions
Disclaimer: The Roof Pitch Calculator is provided for general planning and educational purposes only. Results are geometric estimates and do not constitute structural engineering, architectural, roofing, or code-compliance advice. Final dimensions, roof pitch, panel requirements, drainage, wind loads, snow loads, framing, and structural design must be verified by the building manufacturer, local authorities, and a qualified design professional.