Roof Pitch Calculator
Enter roof rise and run to instantly compute pitch angle, pitch percentage, slope length and roof area. Essential for village houses, rooftop and zinc-roof works.
Input Data
Results
At a glance:The roof pitch calculator models the roof section as a right triangle: rise is the vertical leg, run is the horizontal leg, slope length is the hypotenuse. Pitch angle is the arctangent of rise/run; pitch percentage is rise/run × 100; slope length comes from Pythagoras; roof area is slope length × eave length.
Formula
Pitch angle θ = atan(rise / run)
Pitch % = rise / run × 100
Slope length = √(rise² + run²)
Roof area = slope length × eave length
Example: rise 1m, run 4m → θ≈14°, pitch 25%, slope 4.12m
$$\theta = \arctan\left(\frac{rise}{run}\right)$$$$p\% = \frac{rise}{run} \times 100$$$$slope = \sqrt{rise^2 + run^2}$$$$A = slope \times L$$How to Use
- Enter the roof rise (ridge height above eave).
- Enter the run (eave-to-ridge horizontal distance).
- Enter the eave length to compute roof area.
- The tool outputs pitch angle, pitch %, slope length and area.
Common roof pitch conversion reference
| Rise/run (per 4m) | Pitch angle | Pitch % |
|---|---|---|
| 0.5m / 4m | ~7.1° | 12.5% |
| 1m / 4m | ~14.0° | 25% |
| 2m / 4m | ~26.6° | 50% |
| 3m / 4m | ~36.9° | 75% |
Steeper pitch sheds rain faster but uses more material; choose by region and appearance.
Case Studies
Village house roof
Village roof rise 1.2 m, run 5 m.
Pitch about 13.5°, 24%.
Slope 5.14 m; eave 8 m gives single-side area about 41.1 m².
Zinc rooftop roof
Rooftop zinc roof addition, rise 0.8 m, run 3 m.
Pitch about 14.9°, slope 3.1 m.
Compare different rises for slope length and material area to pick the cheapest.
Repair quote
The repair master needs the roof material area.
Enter rise and run for slope length, multiply by eave length for single-side area.
For a double-slope roof, double the area.
FAQ
What is pitch angle vs pitch percentage?
Pitch angle is the roof-to-horizontal angle (degrees); pitch percentage is rise/run × 100. They describe the same slope in different units.
How to get both-side area?
The tool gives single-side area = slope length × eave length; for a gable (two-slope) roof, multiply by 2.
Why does pitch matter for materials?
Steeper roofs have longer slope length, so more tiles/sheets and underlayment; very low pitch may need different waterproofing.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.