1. What is Percent Grade?

Percent Grade is a measure of slope steepness expressed as a percentage. It represents the ratio of vertical rise to horizontal run, multiplied by 100 to convert to percentage form.

2. How Does the Calculator Work?

The calculator uses the percent grade formula:

Where:

• \( rise \) — Vertical change (in units like meters or feet)
• \( run \) — Horizontal change (in units like meters or feet)
• \( 100 \) — Percentage conversion factor (unitless)

Explanation: The formula calculates the slope as a percentage by dividing the vertical rise by the horizontal run and multiplying by 100.

3. Importance of Percent Grade Calculation

Details: Percent grade calculation is essential in civil engineering, construction, road design, and various outdoor activities. It helps determine slope steepness for safety, design specifications, and accessibility requirements.

4. Using the Calculator

Tips: Enter both rise and run values in the same units (meters, feet, etc.). Both values must be positive numbers, with run greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between percent grade and angle?
A: Percent grade expresses slope as a percentage (rise/run × 100), while angle expresses it in degrees. They measure the same concept but in different units.

Q2: What is considered a steep grade?
A: Generally, grades above 10% are considered steep for vehicles, while grades above 15-20% are challenging for pedestrians.

Q3: Can percent grade be negative?
A: Yes, negative percent grade indicates a downward slope (decline), while positive indicates upward slope (incline).

Q4: How is percent grade used in road construction?
A: Road designers use percent grade to ensure safe vehicle operation, proper drainage, and compliance with accessibility standards.

Q5: What's the maximum percent grade for wheelchair accessibility?
A: ADA guidelines recommend a maximum slope of 8.33% (1:12 ratio) for wheelchair ramps.