1. What is Slope Percentage?

Slope percentage is a measure of steepness expressed as a percentage, representing the vertical rise divided by horizontal run multiplied by 100. It is commonly used in civil engineering, construction, and road design to describe incline gradients.

2. How Does the Calculator Work?

The calculator uses the trigonometric formula:

Where:

• \( Slope \% \) — Slope percentage
• \( \theta \) — Angle in degrees
• \( \tan \) — Trigonometric tangent function

Explanation: The tangent of an angle in a right triangle equals the ratio of opposite side (rise) to adjacent side (run). Multiplying by 100 converts this ratio to a percentage.

3. Importance of Slope Calculation

Details: Accurate slope calculation is essential for road design, drainage planning, wheelchair ramp construction, roof pitch determination, and ensuring proper grading for construction projects.

4. Using the Calculator

Tips: Enter the angle in degrees (0-90). The calculator will convert the angle to slope percentage. For angles approaching 90 degrees, slope percentage increases dramatically.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between slope percentage and slope ratio?
A: Slope percentage is rise over run × 100, while slope ratio is expressed as rise:run (e.g., 1:4 for a 25% slope).

Q2: What slope percentage is considered steep?
A: Generally, 10-15% is moderate, 15-20% is steep, and above 20% is very steep. Maximum recommended for roads is typically 6-8%.

Q3: How does slope percentage relate to degrees?
A: 0° = 0%, 45° = 100%, 90° = infinite%. The relationship is non-linear due to the tangent function.

Q4: What is the maximum slope for wheelchair ramps?
A: ADA guidelines recommend maximum 8.33% slope (1:12 ratio) for wheelchair ramps.

Q5: Can I calculate slope percentage without trigonometry?
A: Yes, if you know rise and run: Slope % = (rise ÷ run) × 100. This calculator uses degrees for convenience.