ADA Ramp Calculator

Calculate ADA-compliant wheelchair ramp dimensions including slope, length, landings, and switchback layout. Free accessibility ramp calculator.

Calculate ADA-compliant wheelchair ramp dimensions including slope, horizontal run, number of landings, switchback layout, and handrail requirements. Enter the total rise (height change) to get a complete ramp design.

Ramp Parameters

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What is an ADA Ramp Calculator?

An ADA Ramp Calculator is a specialized tool for designing wheelchair ramps that comply with the Americans with Disabilities Act (ADA) Standards for Accessible Design. It calculates the required ramp length, number of landings, switchback layout dimensions, and handrail specifications based on the height change (rise) you need to overcome. ADA-compliant ramps ensure safe and independent access for people using wheelchairs, walkers, and other mobility aids.

ADA Ramp Requirements

Maximum slope: 1:12 (one inch of rise for every 12 inches of run, or 8.33%)
Maximum rise per run: 30 inches (762 mm) before a landing is required
Minimum clear width: 36 inches (914 mm) between handrails
Landings: minimum 60" × 60" (1524 mm × 1524 mm) at top, bottom, and turns
Handrails: required on both sides when rise exceeds 6 inches (152 mm)
Handrail height: 34" to 38" (864 mm to 965 mm) from ramp surface
Handrail extensions: 12 inches (305 mm) beyond top and bottom of ramp
Edge protection: curbs, walls, or railings to prevent wheelchair wheels from slipping off

How to Calculate Ramp Length

The basic formula for ramp length is: Ramp Run = Total Rise × Slope Ratio. For a standard 1:12 ADA ramp, multiply the rise by 12. For example, a 30-inch rise requires 360 inches (30 feet) of horizontal run. Add 60 inches for each landing (top, bottom, and intermediate). If the total rise exceeds 30 inches, divide the ramp into multiple segments with intermediate landings between them.

Switchback vs. Straight Ramp

A straight ramp extends in one direction and requires significant horizontal space. A switchback ramp folds back on itself with 180-degree turns at landings, saving horizontal space but requiring more width. Switchback ramps are ideal when space is limited. The switchback footprint width is calculated as twice the ramp clear width plus a 12-inch gap between the parallel runs. The length equals one segment run plus one landing length.

Tips for Ramp Design

Use a 1:12 slope or gentler whenever possible for maximum accessibility
The 1:10 and 1:8 slopes are only permitted for existing buildings where space is extremely limited
Consider a switchback layout to reduce the footprint in tight spaces
Provide non-slip surfaces on the ramp and landings for safety in all weather conditions
Ensure adequate drainage so water does not pool on the ramp surface
Landings at turns must be at least 60" × 60" to allow wheelchair turning
Handrails should be graspable with a circular cross-section of 1.25" to 2" diameter
Always check local building codes as they may exceed ADA minimum requirements