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Slope Calculator — Calculate Grade Percentage & Angle
Calculate slope, grade percentage, and angle free. Enter rise and run to find slope for construction, landscaping, or roofing. Use the interactive slope calculator below to get a fast browser-based result without creating an account.
Use the controls below. The widget loads automatically when this tool page opens.
How Do You Calculate Slope Percentage?
Divide rise by run, then multiply by 100. A 3 inch rise over a 36 inch run equals 8.33%, with an angle of about 4.76 degrees.
How to Use Slope Calculator
- 1Open the widget
Use the Slope Calculator controls at the top of this page.
- 2Enter your input
Enter the measurements, quantities or settings requested by Slope Calculator, then review the calculated total.
- 3Run and review
Review the slope calculator result, compare the supporting details, then change the inputs to test another scenario.
About slope calculator
Slope Calculator focuses on slope calculator and related needs such as slope calculator, grade percentage calculator, slope grade calculator, rise over run calculator. The interactive widget appears before the long explanation so search visitors can solve the task first, then read the supporting notes if they need context.
Slope Calculator estimates everyday home, hobby or reference values from your inputs. It works best when you measure carefully and include a practical margin for real-world variation.
For best results, start with clean inputs, run the tool once, then review the supporting details before using the output. If the result affects money, health, publishing, legal work or a public file, verify the final answer with another trusted source.
Frequently Asked Questions
How do I calculate slope percentage?
Slope percentage is rise divided by run, multiplied by 100. For example, 3 inches of rise over 36 inches of run is 8.33%.
What is the slope formula?
The basic slope formula is rise over run. This calculator also converts the same grade into a ratio, angle in degrees, radians and roof pitch.
What percentage slope is considered steep?
For everyday reference, 1% to 2% is gentle drainage, 8.33% is a common maximum ADA ramp grade, 25% is a steep residential driveway and 100% is a 45 degree slope.
How do I convert slope angle to percentage?
Convert an angle to slope percentage with tan(angle in degrees) x 100. Convert slope percentage back to angle with atan(percent / 100).