ADA Ramp Calculator
Enter the total rise and slope ratio to calculate the ramp run, number of landings, total length, and handrail footage for an ADA-compliant wheelchair ramp.
Estimate only — not professional advice. Always verify results independently before purchasing materials or beginning work. Terms of Use
What is ADA Ramp?
An ADA ramp calculator determines the dimensions of a wheelchair-accessible ramp that complies with the Americans with Disabilities Act (ADA) accessibility standards. The ADA sets strict requirements for ramp slope, width, landing frequency, and handrail design to ensure safe, independent access for wheelchair users and people with mobility impairments. This calculator translates a simple rise measurement into the full ramp layout including run, landings, total length, and handrail material. The fundamental ADA requirement is a maximum slope of 1:12, meaning one inch of rise for every 12 inches (one foot) of horizontal run. A 24-inch rise therefore requires a minimum run of 24 feet. Steeper slopes (such as 1:8 or 1:10) are only permitted for existing buildings where space constraints make 1:12 impossible, and only under specific conditions. The 1:12 ratio provides a manageable grade for self-propelled wheelchair users and is the standard for all new construction. Landings are level platforms required at the top and bottom of every ramp and at intervals along the run. ADA requires a landing after every 30 feet of ramp run (measured horizontally, not along the slope). Landings must be at least 60 inches (5 feet) long in the direction of travel and at least as wide as the ramp. They provide rest areas and space for wheelchair users to stop safely. The calculator adds one landing at the top, one at the bottom, and one intermediate landing for every 30 feet of run. Handrails are required on both sides of any ramp with a rise greater than 6 inches. They must be continuous along the full length of the ramp and extend 12 inches beyond the top and bottom of each ramp segment. Handrail height must be between 34 and 38 inches, and the gripping surface must be between 1.25 and 2 inches in diameter. The calculator estimates total handrail linear footage as twice the total ramp length (both sides), providing a baseline for material ordering. Ramp width is measured between the handrails. The ADA minimum is 36 inches clear width, but 48 inches is recommended for high-traffic areas and required where two wheelchairs must pass. The width affects the amount of decking, framing, and railing material but does not change the run or landing calculations. Proper ramp design is not just a legal requirement — it provides dignity, safety, and independence for all users.
How to Calculate
- Measure the total vertical rise from the lower surface to the upper surface in inches
- Select the slope ratio (1:12 is the ADA maximum for new construction)
- Set the landing depth (5 feet is the standard ADA minimum)
- Enter the ramp width (36 inches minimum per ADA)
- Review the ramp run, number of landings, total length, and handrail material
- Verify the design fits the available space on site
- Consult local building codes for additional requirements beyond ADA minimums
Formula
Ramp Run = Total Rise (in) x Slope Ratio / 12 Landings by Run = ceil(Ramp Run / 30) Landings by Rise = ceil(Total Rise / 30) Intermediate Landings = max(0, max(Landings by Run, Landings by Rise) - 1) Total Landings = Intermediate Landings + 2 (top and bottom) Total Length = Ramp Run + (Total Landings x Landing Depth) Handrail Linear Feet = 2 x Total Length (both sides) The slope ratio converts inches of rise to feet of run. ADA 2010 imposes two separate landing triggers: a single ramp run may not exceed 30 feet of horizontal run, and (per §405.6) a single run may not rise more than 30 inches without an intermediate landing. The calculator evaluates both limits and uses whichever requires more landings. Mandatory top and bottom landings are always added. Handrails run the full length on both sides.
Example Calculation
A ramp with 24 inches of total rise, 1:12 slope, 5 ft landings, 36-inch width: Ramp Run = 24 x 12 / 12 = 24 ft Landings by Run = ceil(24 / 30) = 1 Landings by Rise = ceil(24 / 30) = 1 Intermediate Landings = max(0, max(1, 1) - 1) = 0 Total Landings = 0 + 2 = 2 (top and bottom only) Total Length = 24 + (2 x 5) = 24 + 10 = 34 ft Handrail = 2 x 34 = 68 linear feet The ramp is short enough that neither limit is exceeded — its run is under 30 ft and its 24-inch rise is under the 30-inch single-run limit — so no intermediate landings are needed, only the required top and bottom landings.
Frequently Asked Questions
What is the maximum slope allowed by ADA for a ramp?
The maximum slope for new construction is 1:12 (one inch of rise per 12 inches of run, or 8.33 percent grade). For existing buildings where space is limited, slopes up to 1:10 are allowed for rises up to 6 inches, and 1:8 for rises up to 3 inches. These steeper slopes are only for alterations to existing structures, not new construction.
How often do I need landings on a ramp?
ADA requires a level landing after every 30 feet of ramp run. Landings are also required at the top and bottom of every ramp and at every change of direction. Landings must be at least 60 inches (5 feet) long in the direction of travel. Where the ramp changes direction at a landing, the landing must be at least 60 by 60 inches.
What is the minimum width for an ADA ramp?
The minimum clear width between handrails is 36 inches. This is sufficient for a single wheelchair. For high-traffic areas or where two-way wheelchair traffic is expected, 48 inches or wider is recommended. Some state and local codes require wider ramps, so check local requirements.
Are handrails required on both sides?
Yes. ADA requires continuous handrails on both sides of any ramp segment with a rise greater than 6 inches. Handrails must be 34 to 38 inches above the ramp surface, and they must extend at least 12 inches horizontally beyond the top and bottom of each ramp run. The extensions must return to the post or wall to prevent snagging.
Can I use a switchback design to save space?
Yes. Switchback (zigzag) ramps are common where space is limited. Each straight run must meet the 1:12 slope and 30-foot maximum run requirements. The landing at each turn must be at least 60 by 60 inches to allow a wheelchair to make a 180-degree turn. A switchback doubles the ramp back alongside itself, significantly reducing the footprint length.
What materials can I use to build an ADA ramp?
Common materials include pressure-treated lumber, composite decking, concrete, and aluminum. Wood ramps are the most common for residential applications. The surface must be slip-resistant, stable, and firm. Concrete ramps need a broom finish for traction. Wood and composite ramps should not have gaps wider than 1/2 inch. Aluminum modular ramp systems offer quick installation and easy reconfiguration.