Slope & Roof Pitch Calculator (Degrees ⇄ Percentage)
Easily calculate and convert slope between percentage (%), degrees (°), elevation drop, and rake rafter length for roofs, gutters, and wheelchair ramps.
Interactive Geometric Slope Triangle Diagram
α = 16.7° (30.0%)How to Calculate and Convert Slope in Percentage and Degrees
Slope calculations are a core trigonometric discipline across civil engineering, carpentry, and architectural design. Whether evaluating roof pitch compliance with building codes, setting sewage drainage falls, or constructing handicap wheelchair ramps, slope is expressed in percentage (grade) or pitch degrees. BenTools' slope calculator computes all triangle dimensions in real-time: rafter length, total vertical rise, and horizontal run.
Key Advantages of the BenTools Slope Calculator
Provide any two dimensions among vertical rise, horizontal run, percentage, or pitch angle: all remaining metrics are instantly derived.
See the slope triangle dynamically tilt and adapt to your exact angle and proportions with live dimension overlays.
Quickly access tile roofing, corrugated metal sheet standards, and instantly verify if your ramp satisfies legal accessibility guidelines.
Recommended Slopes by Construction Project & Standards
| Construction Type | Typical Slope (%) | Pitch Angle (°) | Rise per Meter | Standard / Code Reference |
|---|---|---|---|---|
| Sanitary wastewater drainage pipe | 1% to 2% | 0.6° to 1.1° | 1 to 2 cm / m | Plumbing code (gravity flow) |
| Corrugated metal roofing / sandwich panels | 5% to 10% | 3° to 6° | 5 to 10 cm / m | Standard metal roofing guidelines |
| Interlocking clay / concrete roof tiles | 30% to 50% | 17° to 27° | 30 to 50 cm / m | Pitched roof code |
| Natural slate pitched roof | 40% to 80% | 22° to 39° | 40 to 80 cm / m | Slate roofing specifications |
| Wheelchair accessibility ramp (ADA / PMR) | Max 5% (1:20 continuous) | Max 2.9° | Max 5 cm / m | ADA Standards for Accessible Design |
Frequently Asked Questions (FAQ) on Slope & Roof Pitch
Why does a 100% slope equal 45 degrees rather than 90 degrees?
Slope percentage measures the ratio of vertical rise to horizontal run multiplied by 100. A 100% slope indicates 1 meter of rise for every 1 meter of run. In an isosceles right triangle, the angle is arctan(1) = 45°. A 90° angle represents a perfectly vertical wall.
What is the minimum required slope for corrugated metal roofing?
According to standard roofing guidelines, the minimum pitch for corrugated sheet metal panels is 5% to 7% (approx. 3° to 4°) for continuous panels, and at least 10% (approx. 6°) when transversal overlaps or heavy rains are present.
How do you calculate the required ramp length for wheelchair access?
ADA standards mandate a maximum slope of 1:20 (5%). For an elevation rise of 20 cm (0.2 m), the required horizontal run is D = 0.2 / 0.05 = 4 meters of ramp.
What is the difference between slope and cross-fall in roadway design?
Slope refers to longitudinal inclination along the direction of traffic travel, whereas cross-fall refers to transverse tilt perpendicular to the road axis designed to shed storm water into drainage ditches.
About the BenTools Slope & Pitch Calculator
Automated calculation optimization & decision support
Automated optimization: Smart financial flow and real-cost simulation, dynamic forward-looking amortization schedules and net yield models, with continuous alignment to benchmark thresholds (real-time gold/silver Nisab rates and FX feeds).
Moroccan Dirham (MAD), Euro (EUR), US Dollar (USD) & official benchmarks
Comprehensive support for flagship currencies and benchmarks: Moroccan Dirham (MAD), Euro (EUR), and US Dollar (USD). For Zakat al-Maal, the Nisab threshold is dynamically assessed using official gold (85g) and silver (595g) benchmark values in local currencies. For lunar date calculations, algorithms include moon-sighting calibrations across North Africa and the Middle East.