Math

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Slope Percentage Calculator.

Convert rise and run to grade percentage and angle.

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Set your values

Results update as you type.

Result: gradePercent: 10.00000000 · angleDegrees: 5.71059314

Result

gradePercent: 10.00000000 · angleDegrees: 5.71059314

Use Cases

Construction and Landscaping

Determine the steepness of driveways, ramps, or terrain to ensure proper drainage or accessibility.

Example: A driveway rises 2 feet over a run of 20 feet, giving a 10% slope.

Road and Trail Design

Check if a path or road meets grade requirements for safety or accessibility standards.

Example: A hiking trail with a 5% grade is considered moderate.

Frequently Asked Questions

How do I calculate slope percentage?
Divide the rise (vertical change) by the run (horizontal distance) and multiply by 100. For example, a rise of 3 feet over a run of 100 feet gives a slope percentage of 3%.
What is the difference between slope percentage and angle?
Slope percentage is the rise divided by run times 100, while angle is the arctangent of that ratio in degrees. This calculator gives the percentage, not the angle.
Can I use any units for rise and run?
Yes, as long as both are in the same unit (e.g., feet, meters). The calculator computes the ratio, so units cancel out.

Tips & Common Mistakes

Tips

  • Ensure rise and run are in the same units before entering them.
  • For very small slopes, the percentage may be less than 1% – that's normal.
  • Use a tape measure or level for accurate rise and run measurements.
  • Remember that a 100% slope corresponds to a 45-degree angle.

Common Mistakes to Avoid

  • Mixing units, like feet for rise and meters for run, which gives incorrect results.
  • Forgetting to multiply by 100 – the calculator does it for you, but manual checks need it.
  • Using the total distance (hypotenuse) instead of the horizontal run.

Last updated: August 13, 2026