🛗 Ramp Calculator
Find the minimum ramp length and angle needed to overcome a given rise, based on a standard slope ratio like the ADA-recommended 1:12.
What this calculator does
The ramp calculator finds the minimum length a ramp needs to be to safely overcome a given rise in height, based on a chosen slope ratio.
The formula
A slope ratio like 1:12 means for every 1 inch of vertical rise, the ramp needs 12 inches of horizontal run. This is the maximum slope allowed by the ADA Standards for Accessible Design for wheelchair-accessible ramps. Multiplying your rise by the slope ratio gives the minimum ramp length, and the arctangent of 1 divided by the ratio gives the resulting incline angle.
This is a general planning estimate. Accessible ramps also have specific requirements for landings, handrails, and edge protection — consult the applicable building code for a code-compliant design.