Work out ramp length instantly with clear inputs, formula shown and shareable results.
Ramp length is the rise multiplied by the gradient denominator, so a 600 mm rise at 1 in 12 needs 7.2 metres of slope. Accessibility codes also cap the rise between landings, commonly 500 mm at 1 in 12 and 750 mm at 1 in 15, so a tall rise needs intermediate landings that add to the overall run.
Ramp length
Length = rise x gradient denominator; gradient percent = 100 / denominator
Landings
Flights = ceil(rise / maximum rise per flight); landings = flights - 1
Preliminary estimate only. Accessible ramp gradients, landings, widths and handrails must comply with the accessibility code adopted locally.
Length = rise x gradient denominator; gradient percent = 100 / denominator. Ramp length is the rise multiplied by the gradient denominator, so a 600 mm rise at 1 in 12 needs 7.2 metres of slope.
A 1 in 12 slope is at the limit of what a manual wheelchair user can self-propel. At 1 in 20 no landings are required at all and the ramp is usable unaided by far more people.
This calculator takes 3 inputs: Total rise, Maximum gradient, Landing length. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.