## How to calculate the ramp slope angle

## What is the slope angle

The slope angle, also known as the inclination angle or grade of a surface, is a measure of the steepness of a ramp, road or surface. It is typically measured in degrees and is the angle between the surface and the horizontal plane. The slope angle is a ratio between the rise (the vertical distance) and the run (the horizontal distance) of a surface. A slope with a higher angle will be steeper and a slope with a lower angle will be more gradual.

For example, a slope with a rise of 6 feet and a run of 12 feet will have an angle of 26.57 degrees, which is a steeper slope than one with a rise of 3 feet and a run of 12 feet, which has an angle of 14.04 degrees.

It’s important to note that calculate the slope angle is not the only factor to consider when designing a ramp or surface for accessibility or safety. Other factors such as the width of the ramp, the presence of handrails, surface conditions, and the intended use of the ramp should also be taken into consideration.

It’s also worth mentioning that the slopes are categorized as positive and negative slopes. Positive slope means the incline is up and negative slope means the incline is down.

## How to calculate the ramp slope angle

The slope angle of a ramp is typically measured in degrees and is determined by the ratio of the rise (the vertical distance) to the run (the horizontal distance) of the wheelchair ramp. The slope angle is calculated using the following formula:

Slope angle (degrees) = arctan (rise / run)

For example, if the rise of a ramp is 3 feet and the run is 12 feet, the slope angle would be:

Slope angle (degrees) = arctan (3 / 12) = arctan (0.25) = 14.04 degrees

It’s important to note that the Americans with Disabilities Act (ADA) recommends a maximum slope of 1:12 (or 8.33 degrees) for ramps that are part of a building and a maximum slope of 1:10 (or 9.43 degrees) for ramps that are located outdoors.

It’s also important to remember that the slope angle is not the only factor to consider when designing a ramp for accessibility. The width of the ramp and the presence of handrails are also important considerations, and must comply with the ADA guidelines.