Calculadora de Porcentagem de Inclinação
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
inclinação% = (rise / run) × 100
About this calculator
The Slope Percentage Calculator converts the ratio of vertical rise to horizontal run into a percentage grade. The formula is straightforward: divide the rise by the run and multiply by 100. For instance, a ramp that rises 2 meters over 10 meters of horizontal distance has a 20% slope. This tool is essential in construction, surveying, and civil engineering to ensure ramps and roads meet safety standards.
How to use: enter the rise and run values in any consistent units (meters, feet, etc.). The calculator instantly returns the slope percentage. It is useful for checking wheelchair ramp accessibility (maximum recommended slope of 8.33% per ADA guidelines), designing roads on hilly terrain, or calculating roof pitches. Note: slope percentage is not the same as the angle in degrees, though they correlate.
Precautions: ensure rise and run are in the same unit. For very small or large slopes, the percentage can be misleading: a 100% slope equals 45 degrees, not 90 degrees. Also, in topographic maps, slope is often given as a percentage, but in drainage or road projects, degrees or ratios may be used. Always check the relevant technical standards for your project before applying the result.
Frequently asked questions
What is the difference between slope percentage and angle in degrees?
Slope percentage is calculated as (rise/run) × 100, while the angle in degrees is the arctangent of that ratio. For example, 100% corresponds to 45 degrees, not 90 degrees.
Can I use different units for rise and run?
No, the units must be the same (both in meters, feet, etc.), as the formula requires consistency for a correct result.
What is the maximum slope allowed for wheelchair ramps in the US?
According to ADA guidelines, the maximum recommended slope is 8.33% (1:12) for ramps with a rise of up to 30 inches, with lower limits for longer rises.
How do I convert slope percentage to degrees?
Use the formula: angle = arctan(rise/run). On calculators, use the inverse tangent function. For example, a 10% slope corresponds to approximately 5.71 degrees.
Can this calculator be used for roofs?
Yes, roof pitch is often expressed as a percentage or ratio (e.g., 30%). The calculator can help convert the rise/run ratio to a percentage.