CVI Medical rents ramps from 2ft - 8ft long ramps. The height of the rise will determine the length of ramp to safely use. For public use, for every in of rise, you need a foot of ramp. For private residences it would be best to follow public safety guidelines but you can use a 2 inch : 1 foot ratio. The steeper your incline is, the harder it will be for individuals to use it safely.