Access Ramp Length Calculator

A disabled woman being wheeled down a rampFor disabled people in mobility scooters or wheelchairs, getting up stairs is not possible. In these cases a ramp will need to be installed to allow the person to ride up at a steady incline. In these cases, however, it’s important that you follow the regulations to ensure a safe access ramp.

You can use our calculator to find the required slope length. Enter the rise (height) in inches from the ground to the raised platform and click “Calculate”.

Ground to raised platform (inches): ADA Standard (1:12 ratio) IRC Minimum (1:8 ratio)

Feet (Max.) Feet

* Recommend referring to the maximum rise guidelines to meet ADA or IRC requirements. Details are outlined below.


ADA Standard

The ADA Standard specifies a maximum ramp length of 1:12. In other words, 12 inches of length for every inch of rise. Not only that, they also specify a maximum rise of thirty inches and minimum width of 36 inches. For more important information about the ADA standards please refer to this document.


IRC Minimum

As above, the maximum ratio of length to rise is 1:12. For ramps which exceed this there must be a handrail placed at a height of around 34 to 38 inches. As of 2015 the minimum 1:8 ratio may be used for both interior and exterior ramps unless the ramp leads down from an egress door (a double door used for evacuation purposes). More information can be found on this page.

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