Wheelchair Ramp Length Calculator

How it is calculated

Enter the vertical rise in centimetres and the slope as the second number of a 1:N ratio (12 for 1:12). The tool multiplies: run = rise × N, then shows that horizontal run in centimetres, metres (÷ 100) and feet (÷ 30.48). If the slope is left empty, zero or negative, it uses 12, the 1:12 maximum slope. The rise must be greater than zero. Note that the figure is the horizontal distance the ramp covers on the ground, not the length of the sloping surface, which is slightly longer. The calculation also leaves out landings, which building codes may require at the top, bottom and at long runs, so check the rules that apply where you are.

Common mistakes

• Entering the rise in inches or millimetres. The tool expects centimetres, so an 8 inch step must be entered as about 20 cm, not 8.
• Typing the slope as a percentage or a decimal such as 8.33 or 0.083. The field is the N in 1:N, so 1:12 is entered as 12.
• Buying a ramp for the horizontal run alone. The surface is slightly longer, and landings, handrail extensions and turns need extra space that this tool does not count.
• Treating 1:12 as the comfortable slope. It is a maximum; a steeper ramp is harder to push, and a larger N like 16 or 20 is easier if you have the room.