We quite often receive requests for wheelchair ramps from people who don’t really know how long the ramp should be to be safe on the step they are tying to make accessible.
As a general rule most ramp manufacturers recommend a gradient no steeper than 1:12 for independant use and 1:6 for assisted use.
A simple calculation for finding out ramp lenghs is to multiple the height by the ratio.
i.e. if working on a 1:6 ratio multiply the height of step by 6 to give you the minimum lengh of ramp
6″ step x 6 = 36″ (3ft ramp)