Accessibility gradients and required ramp lengths

cm
Height difference to overcome, in centimeters.
5 %
m
Horizontal length available for the ramp, in meters.

Generic accessibility guidance — local building codes and accessibility regulations always prevail.

Ramp length
Slope
Angle
Ratio

Required length at common slopes

Slope Ratio Required length

About Ramp Slope Calculator

The ramp slope calculator sizes accessibility ramps. Give it the height to overcome and it either tells you how long the ramp must be at a chosen slope, or — if your space is fixed — checks whether the length you have produces an acceptable gradient. Results show the slope as a percentage, an angle, and a 1:n ratio.

The verdicts follow widely used accessibility guidance: slopes of 5% (1:20) or gentler are comfortable for wheelchair users, slopes up to 8% (roughly 1:12) are acceptable for short runs with landings, and anything steeper is flagged as too steep for independent wheelchair use.

A reference table lists the required ramp length at every common slope for your rise, and a side-view diagram updates live. It is a free browser tool for quick feasibility checks on entrances, thresholds, and site paths — local accessibility regulations always take precedence over these generic values.

How to use Ramp Slope Calculator

  1. Enter the total rise to overcome, in centimeters.
  2. Choose a mode: find the required length from a slope, or check the slope of your available length.
  3. Set the slope percentage or the available horizontal length in meters.
  4. Read the ramp length, slope, angle, and ratio, plus the accessibility verdict.
  5. Compare alternatives in the required-length table for common slopes.

Frequently asked questions

Divide the rise by the slope. A 50 cm rise at a 5% slope needs 0.5 ÷ 0.05 = 10 m of horizontal run. Halving the slope doubles the length, which is why gentle ramps get long quickly.

A gradient of 5% (1:20) or less is comfortable for most wheelchair users. Up to 8% — close to the 1:12 maximum in many codes — is acceptable only for short runs broken up by level landings.

One unit of rise for every twelve units of horizontal run: a 30 cm step needs 3.6 m of ramp. As a percentage that is about 8.3%, or an angle of roughly 4.8 degrees.

Yes. Most accessibility standards require a level resting landing at regular intervals — commonly every 9 m of run or at every 50 cm of rise — plus landings at the top, bottom, and any change of direction.

They follow generic accessibility guidance, but maximum slopes, landing sizes, widths, and handrail rules differ by country and building type. Always confirm the final design against your local building code and accessibility regulations.

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