Calculate Slope Percentage
Choose a method, enter your values, and get the grade result instantly.
What Is Slope Percentage?
Slope percentage shows how much a surface rises or falls over a horizontal distance. A 10% slope means the surface rises 10 units for every 100 units of horizontal run. It is commonly used in civil work, ramps, roofing, roads, drainage lines, and landscape grading.
Road & Driveway Grade
Estimate how steep a driveway, road section, path, or access ramp is before planning work.
Ramp Planning
Convert rise and run into slope percentage to understand ramp incline more clearly.
Drainage Direction
Check whether a surface has enough fall for water flow, garden grading, or drainage layout.
How This Slope Calculator Works
The calculator uses standard slope formulas and converts your input into percentage, angle, and ratio so you can understand the incline in different formats.
Slope Percentage Formula
Use this formula when you already know the rise and horizontal run:
Slope Percentage = (Rise ÷ Run) × 100
Example: If the rise is 5 feet and the run is 100 feet, the slope percentage is: (5 ÷ 100) × 100 = 5%.
| Rise | Run | Slope Percentage | Meaning |
|---|---|---|---|
| 1 | 100 | 1% | Very gentle slope |
| 5 | 100 | 5% | Moderate grade |
| 10 | 100 | 10% | Noticeably steep |
| 20 | 100 | 20% | Very steep incline |
FAQs
Common questions about slope percentage, grade, rise, run, angle, and ratio conversion.
How do you calculate slope percentage?
Divide the rise by the run, then multiply the result by 100. The formula is: slope percentage = (rise ÷ run) × 100.
What does a 5% slope mean?
A 5% slope means the surface rises or falls 5 units for every 100 units of horizontal distance. For example, 5 feet of rise over 100 feet of run equals a 5% slope.
Is slope percentage the same as degrees?
No. Slope percentage and degrees are different ways to describe incline. Percentage is based on rise over run, while degrees measure the angle of the slope.
Can this calculator measure downward slopes?
Yes. Enter a negative rise value to calculate a downward slope. The result will show a negative percentage.
What units should I use for rise and run?
You can use feet, meters, inches, or centimeters, but rise and run must use the same unit for an accurate result.