Slope Percentage Calculator
Slope percentage describes vertical change relative to horizontal distance, with a sign that indicates uphill or downhill. It is commonly used for grades, ramps and land measurements.
How to use this calculator
- Enter signed vertical change and horizontal run in consistent units.
- Check that all inputs use the same units, period and population scope.
- Change one assumption at a time when comparing scenarios.
Formula used by slope percent calculator calculator
Slope % = vertical change ÷ horizontal run × 100; angle = arctan(vertical change ÷ run).
- Slope % = vertical change ÷ horizontal run × 100; angle = arctan(vertical change ÷ run).
- Use horizontal run rather than sloped surface length. Accessibility and drainage requirements depend on local standards and the context.
- The tool validates inputs and rounds displayed figures for readability; it does not validate assumptions against external records.
Worked examples
Worked example
A rise of 1.5 over a horizontal run of 12 gives a 12.5% slope.
1.5 ÷ 12 × 100 = 12.5%.
The slope is 12.5% and about 7.13 degrees.
Understanding the result
Slope percentage describes vertical change relative to horizontal distance, with a sign that indicates uphill or downhill. It is commonly used for grades, ramps and land measurements.
Use horizontal run rather than sloped surface length. Accessibility and drainage requirements depend on local standards and the context.
Important notes
Use horizontal run rather than sloped surface length. Accessibility and drainage requirements depend on local standards and the context.
Treat the result as an estimate from the entered assumptions. For safety, legal, engineering, health or commercial decisions, verify relevant specifications and professional guidance.
Frequently asked questions
Can slope be negative?
Yes. Negative rise indicates a downward change in the chosen direction.
Is 100% slope 90 degrees?
No. 100% means rise equals run, corresponding to 45 degrees.
How should I interpret this result?
Use horizontal run rather than sloped surface length. Accessibility and drainage requirements depend on local standards and the context.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
- How to Calculate Percentage Change — Learn the percentage change formula, how to calculate increases and decreases, and why the original value matters.
- Percentage Change vs Percentage Difference — Understand the difference between percentage change and percentage difference, including when each formula is appropriate.
- Percentage Change — Learn what percentage change means, how to calculate increases and decreases, and how the original value affects the result.
This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.