1. What is Percent Grade Incline?

Percent grade incline measures the steepness of a slope, expressed as a percentage. It represents the vertical rise divided by the horizontal run, multiplied by 100.

2. How Does the Calculator Work?

The calculator uses the percent grade formula:

Where:

• \( Rise \) — Vertical height change (ft)
• \( Run \) — Horizontal distance (ft)

Explanation: The formula calculates the ratio of vertical rise to horizontal run and converts it to a percentage value.

3. Importance of Grade Calculation

Details: Percent grade calculation is essential in construction, road design, landscaping, and accessibility planning to ensure safe and functional slopes.

4. Using the Calculator

Tips: Enter rise and run values in feet. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is considered a steep grade?
A: Generally, grades above 10% are considered steep, while grades above 20% are very steep and may require special considerations.

Q2: How does percent grade relate to angle?
A: Percent grade = tan(angle) × 100%, where angle is measured in degrees from horizontal.

Q3: What are typical grade limits for roads?
A: Major highways typically have maximum grades of 5-6%, while local roads may have grades up to 12-15% in hilly areas.

Q4: Can this calculator be used for metric units?
A: Yes, as long as both rise and run use the same units (meters, centimeters, etc.), the percentage result will be the same.

Q5: What's the difference between grade and slope?
A: Grade is expressed as a percentage, while slope is typically expressed as a ratio (e.g., 1:4) or in degrees.