Wheelchair Ramp FAQs

Q: What Does the ADA Wheelchair Ramp Slope of 1:12 Really Mean?

A: Technically – the ADA recommendation for a wheelchair ramp slope is 1” of height needs 12” of ramp length. This is a 5-degree slope.

Translation – A 5-degree slope is gentle enough for the average wheelchair-bound person to manually push themselves up a wheelchair ramp without assistance. An easy way to think of this ADA recommendation is 1” of height per 1’ of wheelchair ramp. Three steps are about 21” high. So, the ADA recommends a 21’ long ramp.


However, think of an ADA recommendation as a guideline or reference tool, not a requirement. Only cities and counties incorporate this wheelchair ramp slope recommendation into their building codes as a legal requirement. This 1:12 guideline makes the design and use for ‘public space’ construction. It is not required for individual residences. It is rare that a city or county has building codes for temporary residential ramps defined as:

  • a ramp that is not permanently attached to the home
  • a ramp that is easily removed when the need (for a ramp) is no long required.

Wheelchair ramp designs of any length are safe and easy to use for residential use. The length of the ramp is generally dictated by the available space. It is also based on the ability of the caregiver or motorized chair to safely get the patient up and down the ramp.


A wheelchair ramp slope of 2” of height per 1’ (i.e., 18” of height equals a 9 foot ramp) provides an acceptable 10-degree slope for an average caregiver pushing an average weight patient (150-175#). If the patient is significantly heavier or the care giver is frail or over than 70, lengthen the ramp accordingly to provide a gentler slope. For a 90-degree turn at the bottom to get on/off the ramp, 5” of space is needed to make this turn.


Good luck with your project, I hope you find this information helpful.

Q.  How do I figure out the correct wheelchair ramp slope?


A.To obtain your correct wheelchair ramp slope, call 913-553-1488.  Wheelchair Ramps provides this free service 7 days/wk, 9am – 7pm CST. A professional engineer asks the right questions to advise the correct wheelchair ramp slope and length for your situation. Your name or address will not be asked. So, take advantage of talking with a ramp expert at no obligation or cost.


Going down a whelchair ramp slope is dangerous due to the inability of the caregiver to control the weight of the wheelchair. Consequently, a ramp that is too steep is unusable. So never guess at a ramp length.


An ADA recommendation only considesr the height of the steps to calculate the slope. Yet, the weight of the patient and strength of the caregiver pushing the wheelchair are also very significant factors. Therefore, these situations need to be considered when calculating the slope.


Consequently, the correct wheelchair ramp slope lies somewhere between these two extremes:


a.  The ADA recommendation of 1” of height equals 12” of ramp length or 5 degrees. This applies to extremely heavy patients or frail caregivers.
b. The common residential guideline of 2” 10 degrees. This ramp slope is used for an average weight patient (170lbs) and a healthy adult caregiver.


There is one more step once you calculate the wheelchair ramp slope and length. Due to the available space dimensions, the total ramp length must fit within this area. So, the ramp may be straight, ‘L’ shaped or ‘U’ shaped. Right-angle turns require a 5’ x 5’ space for the wheelchair and caregiver.

Q: I need a strong ramp because it needs to go up stairs that are 29” high. Furthermore, it needs to be strong enough for my mother-in-law in a power chair. Any suggestions?

A. First of all, a strong ramp can be built to support any weight. It is just a matter of the number of vertical supports used. Because a power chair is typically 350lbs when occupied, you are looking at a total of about 500-600lbs.


The correct length for sectional ramp construction for 29” high steps needs to be 16’ in order to have the correct wheelchair ramp slope that a power chair can handle. To support this weight, you will need four vertical supports to secure the ramp deck at the 39”, 78”, 117” and 156” marks.


In conclusion, the wheelchair ramp construction documentation that comes with our ramp kit shows how to easily build these supports. Call 913-553-1488, 7 days/wk to visit with an engineer at no cost, regarding any wheelchair ramp slope questions.