Access ramp over highway, Gjadalajara, Mexico © D Friedman at Building Access Ramp Slope or Pitch Requirements
Recommended Access Ramp Angle Slope & Run Length

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Building access ramp slope, pitch or angle specifications & codes: this document provides building code specifications, sketches, photographs, and examples of defects used in inspecting indoor or outdoor building access ramps.

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Building Access Ramp Slope or Pitch Requirements

Stair dimensionsBottom line: the preferred slope for a building access ramp is between 7 and 15 degrees, and permitted slopes range between 0 and 20 degrees.

This article series on access ramp design & construction explains and illustrates the requirements for safe, useable interior and exterior access ramps in buildings.

[Click to enlarge any image]

Readers should note that the design specifications for permitted slope and other specifications for ramps that are not used for building entry or exit, such as curb cuts, are different from those used at building entrances.

For example a steeper slope may be permitted on non-access ramps. For complete details about building access ramp construction: slope, width, railings, non-slip surfaces, steps, landings at ramps, etc. See the standards, code, and ADA REFERENCES at the end of this document.

The combination of a sloped surface with conditions that can make that walking surface slippery, especially at outdoor building access ramps, forms a falling hazard at both ramp ascent, and ramp descent for nearly everyone.

These hazards are particularly increased if the ramp pitch is too steep. The desirable ramp slope standard, one inch of rise in 12 inches of run (about 8.3 percent slope), has been adopted by most building codes regardless of whether or not the access ramp is specifically for people with disabilities.

Our illustrations above and below describe the recommended slope range for building access ramps, fixed stairs, and other structures.

Stair Dimensions

If a building access ramp (also called an egress ramp) is located within an accessible route of travel and is used as a means of egress (exiting from a building), the ramp slope should be 1:12 (4.8 degrees, 8.3 percent) or less in the direction of travel.

This standard is reflected in at least four building standards: UBC 1003.3.4.3, BOCA 1016.3, ADA 4.8.2, IBC 1010.2, and is elaborated in an excellent book that we recommend on stairs and ramps, Slips, Trips, Missteps and Their Consequences, by Bakken et als, found in REFERENCES at the end of this article.

If the ramp is NOT located within an accessible route of egress (say a ramp giving access between the street and an elevated sidewalk), the slope of the ramp may be a little steeper (1:8 rather than 1:12, or 7.1 degrees, or 12.5 percent) in the direction of travel.

Incidentally, depending on terrain, a ramp may slope upwards towards a building entry/exit door, or it may slope downwards towards the entry door. In either case, the ramp slope rules and standards are the same and the trip/fall hazards are essentially the same.

How to measure the slope of an access ramp

  1. Project a horizontal line (use a string, level, and stake if it helps) outwards from the uppermost end of the ramp - say the building entry platform - and the end of the ramp. Keep this line dead level.
  2. Measure the Ramp's Rise: Measure the height (the vertical distance) from the horizontal line to the ground surface at the end of the ramp or its landing platform. This is the total rise of the ramp.
  3. Measure the Ramp's Run: Measure the ramp's total horizontal distance from one end of the ramp to the other - say from the point at which the ramp reaches a level building entry platform or entry door to the opposite end of the ramp.
  4. State the Resulting Ramp Slope: Simply write the total rise divided by the total run to express the slope as a percent (1 inch of rise / 12 inches of run = 8.3% slope), or write the slope as a ratio such as 1:12, also expressed as "one in twelve".

Ramp Slope Example 1: if your ramp is twelve feet long (144 inches) and the rise is twelve inches (12 inches) then the slope of the ramp is 12:144, or simplifying, dividing both sides of the equation by 12, the slope can be written as 1:12 - which meets the desired ADA standard.

Ramp Slope Example 2: If the ramp is twelve feet long (144 inches) and the total rise is four feet (48 inches) then the slope of the ramp is 48:144, or simplifying by dividing both sides of the equation by 12, the slope of this ramp is written as 4:12 (and the ramp is too steep, likely to result in a fall).

Access Ramp Maximum Run Length

Question: what is the maximum ADA-compliant access ramp length

ADA access ramp specifications and maximum ramp run  length (C) adapted from ADA as cited in detail in this document2019/03/01 jack said:

How long can a ramp run before you need a flat landing area ?

Illustrations [above and below] on which we indicate a 30 ft. or 40 ft. (depending on slope) maximum-recommended access ramp length for a single run before reaching a landing or platform, adapted from the United States Access Board,

retrieved 2019/03/01 original source: and from

[Click to enlarge any image]

Reply: Maximum horizontal run for ADA compliant ramps: 30 or 40 ft. depending on slope:

ADA Guidelines for Wheelchair Ramps allow a Maximum run of 30 feet of wheelchair ramp before a rest or turn platform [for ramps with a slope of 1:12 to < 1:16


ADA Guidelines for a single ramp run with a slope of 1:16 to < 1:20 allow a maximum run of 40 feet before a rest or turn platform.

Below are some additional ADA ramp length details

ADA compliant wheelchair access ramp maximum run lengths vs ramp slope (C) adapted from ADA Figure 16 Components of as Single Rmpa Run and Sample Ramp Dimensions

Figure 16. Components of a Single Ramp Run and Sample Ramp Dimensions.

Components include a level landing at the top of the ramp, the surface of the ramp and a level landing at the bottom of the ramp.

The rise of the ramp is the vertical dimension and the horizontal projection or run of the ramp is the horizontal dimension.

If the slope of a ramp is between 1:12 and 1:16, the maximum rise shall be 30 inches (760 mm) and the maximum horizontal run shall be 30 feet (9 m).

If the slope of the ramp is between 1:16 and 1:20, the maximum rise shall be 30 inches (760 mm) and the maximum horizontal run shall be 40 feet (12 m).

A4.8.2 Slope and Rise. Ramp slopes between 1:16 and 1:20 are preferred. The ability to manage an incline is related to both its slope and its length. Wheelchair users with disabilities affecting their arms or with low stamina have serious difficulty using inclines.

Most ambulatory people and most people who use wheelchairs can manage a slope of 1:16. Many people cannot manage a slope of 1:12 for 30 ft (9 m).

4.8.4* Landings. Ramps shall have level landings at bottom and top of each ramp and each ramp run. Landings shall have the following features:

(1) The landing shall be at least as wide as the ramp run leading to it.

(2) The landing length shall be a minimum of 60 in (1525 mm) clear.

(3) If ramps change direction at landings, the minimum landing size shall be 60 in by 60 in (1525 mm by 1525 mm).

(4) If a doorway is located at a landing, then the area in front of the doorway shall comply with 4.13.6.


Access Ramp Landing slope

Separately from the slope of the access ramp walkway itself, in some situations a landing or platform may be required along a rampway, depending on the ramp length and the requirement for turning space.


Landings shall have a slope not steeper than one unit vertical in 50 units horizontal (2-percent slope) in any direction. Changes in level are not permitted. - Florida Building Code 1010.6.1 Landings.


Continue reading at RAMP SLIP TRIP FALL HAZARDS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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