Access Ramps - Choosing the Right Length

Choosing the right length access ramp is pretty easy once you have the formulas.  All you need is a tape measure, a calculator or the handy Ramp Slope Chart (see below) and a keen understanding of what you're trying to accomplish and you'll be able to buy a ramp with the right amount of incline.  You don't want the ramp to be too steep, right?  In fact, the length of the ramp is at least as critical as the width when it comes to safety, but takes some thought and a little planning.

Once you have the length calculated, you can choose the proper width and type of ramp - depending on how and where it will be used.  What a relief to know you will be able to get your mobility scooter into the van; assist an elderly or disabled person up the porch steps; or roll your wheelchair down a terraced walkway with the greatest of ease and safety.

Our buddies at Prairie View Industries (PVI Ramps) shared their ramp slope formulas, ramp slope chart and measurement instructions so we could help you calculate your optimal ramp length.   Thanks PVI!

How Long Should My Ramp Be?

To determine your ramp length you first need to determine the rise.  The rise is the vertical measurement between the ground and where the top of the ramp is going to sit.

Ramp Rise Illustration

Note: If your rise is more than 24" (2 feet) please contact a local dealer about a modular system.

PVI recommends not to exceed a 2:12 slope (9.5° ramp incline) on most applications.  The slope relates to how steep the ramp is, in degrees of incline.  Some ramps may need to meet the ADA's 1:12  (4.8°) more gradual slope requirements, as specified by your state.

To find a 2:12 slope, take the total rise in inches (vertical measurement between the ground and the top of the step or landing) and divide it by 2.  The result is the number of feet of ramp length you need for that rise.

Example: Say you have a 12" rise.  Divide 12 by 2 and you get 6.  So a 12 inch rise requires a 6 foot ramp, using the 2:12 ratio.

1:12 slope (used by the ADA) would require 1 foot length of ramp for every inch of vertical rise.

Slope Recommendations based on Use of Ramp:

  • 1:12 SLOPE (4.8°) - Gradual, gentle incline, longest ramp.  Calculated as 1 foot length of ramp for every 1 inch of total vertical rise (the rise divided by 1).  A 5 inch rise requires a 5 foot ramp, a 12 inch rise requires a 12 foot ramp and so on.  The ADA recommends this slope for long home ramps as well as commercial ramps.  Note:  This 1:12 slope works for most strong, unassisted manual wheelchair users, although PVI always recommends assistance.
  • 2:12 SLOPE (9.5°) - Steeper incline, shorter ramp.  Calculate length of ramp in feet by dividing total rise by 2 (6" of ramp length for every 1" of rise). A 2:12 slope is the maximum acceptable grade (incline) for portable ramps used by occupied chairs and scooters, with a qualified assistant.
  • 3:12 SLOPE (14.5°) - Steepest incline.  Calculate the length of ramp by dividing the total rise by 3 (4 feet of ramp length for every 12 inches of rise).  This 3:12 ratio should be used only for loading and unloading unoccupied chairs and scooters - (in and out of a truck or van, for example).

Ramp Slope Chart

PVI Ramp Incline Chart

Photo courtesy of PVI, Inc.


Access Ramp Safety Guidelines

  • Always have a qualified assistant present when using any portable ramp.
  • Never exceed a slope greater than 2" on 12" (2:12 ratio) with an occupied chair or scooter.  Never exceed a slope greater than 3" on 12" (3:12 ratio) with an unoccupied chair or scooter.
  • Always make sure that the top of the ramp is secured on a step or landing before using.  It may be necessary to anchor the top of the ramp to the landing surface with steel security pins provided.
  • Make certain there is adequate head clearance prior to loading an occupied chair or scooter into a vehicle.
  • Always follow manufacturer recommendations for your chair or scooter.
  • Always use your lap belt.
  • If your ramp comes with a safety DVD, watch it.  All PVI ramps include a DVD.
  • If you need help, please call Allegro Medical at 800-861-3211.

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