Ramp slope (incline) calculation

For a wheelchair ramp to do its job it needs to have the right degree of slope or incline, i.e. the ratio of the ramps length to its height.

If the incline of a ramp is too steep it will prove difficult (and potentially dangerous) for any person in a wheel based vehicle using it. For this reason the guides below should be used to calculate the length-versus-height ratio of a ramp (UK).

USA - For the USA you will be able to find guidance here ADA Accessibility Guidelines for Buildings and Facilities and here ADA Standards home page.

There are separate applicable ratios for permanent and temporary ramps and for self propelled and pushed (by a third party) wheelchairs.

Temporary ramps

1. The following requirements apply for temporary ramps.

• If the ramp is for a wheelchair that is to be self propelled by the person using it, then there must be an allowance of 12 inches (1 foot) in length for every 1 inch in rise.

  E.g. a 1 inch high ramp would be 1 foot in length, a 3 inch high ramp would be 3 feet in length.

• If the ramp is for a wheelchair that is to be pushed by another person (and not the person using it), then there must be an allowance of 6 inches in length for every 1 inch in rise.

  E.g. a 1 inch high ramp would be 6 inches in length, a 3 inch high ramp would be 18 inches (1 1/2 feet) in length.

2. The following requirement applies for permanent or fixed ramps.

• For permanent (i.e. fixed) ramps there is one single ratio (incline) that is acceptable. This incline requires an allowance of 1 foot and 3 inches for each 1 inch rise in the ramps height.

  E.g. a 1 inch high ramp would be 1 foot 3 inches in length, a 3 inch high ramp would be 3 feet and 9 inches in length, a 6 inch high ramp would be 7 feet and 6 inches in length.

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