Ramp Slope Calculator

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About Ramp Slope Calculation

The results are approximate. Before use, verify the calculations against the applicable standards and consult a specialist. The developer is not responsible for the consequences of use without project verification.

The Ramp Slope Calculator computes the rise, horizontal run and inclined length of a ramp from any known values: height, section length, slope ratio (1:x), percent grade, or angle. It works entirely in the metric system and supports straight ramps as well as layouts with 90° or 180° turns. Use it to plan accessible paths, wheelchair ramps and service ramps, and to convert between ratio, grade and angle without manual math.

Tips and Tricks

What the tool counts: only the sloped part of the ramp. Horizontal landings are not included in the length calculation.
Typical European practice: universal-access ramps are often set to about 1:20 (≈5%). The practical upper limit for barrier-free design is about 1:16 (≈6%). Steeper options such as 1:12 (≈8.33%) are for short runs only with mandatory landings; 2:12 (≈16.7%) and 3:12 (≈25%) are technical/assisted and not considered barrier-free.
Landings & turns: provide landings at least 150 cm long, as wide as the ramp, with cross slope up to 2% for drainage. For a 90° turn, common practice is a landing of at least 150 × 150 cm; for a 180° switchback, at least 150 × 180 cm.
Quick example: to overcome a height of 60 cm at 1:16, the horizontal run is 9.60 m and the inclined length is about 9.62 m.
Formulas used: grade % = 100 × rise / run; ratio 1:x where x = run / rise; angle in degrees = arctan(rise / run); inclined length L = √(rise² + run²).
Normative note: values above reflect common European accessibility guidance (e.g., EN-style accessible design practice). Always verify final designs against your local building code.

Preset ratio	Approx. grade, %	Approx. angle, °	Typical use
1:20	≈5	≈2.9	Preferred universal access
1:16	≈6.25	≈3.6	Upper barrier-free limit
1:12	≈8.33	≈4.8	Short sections with landings
2:12	≈16.7	≈9.5	Assisted/technical
3:12	≈25	≈14.0	Technical only

FAQs

How do I calculate ramp slope?

Enter any two values and the calculator will find the rest. Manually, use grade % = 100 × rise / run, or express the same slope as a ratio 1:x where x = run / rise. To get the angle, use angle = arctan(rise / run). This lets you convert between “ramp slope”, “ramp pitch” and “ramp angle” in one step.

What is a good slope for a wheelchair ramp?

For everyday independent use, a gentle ramp around 1:20 (≈5%) is widely preferred. About 1:16 (≈6%) is a common practical maximum for barrier-free routes; anything steeper, such as 1:12, should be short and include level landings. Choose the lowest slope that fits your site to improve comfort and safety.

How long should my ramp be for a given height?

Pick a ratio and multiply: for 1:x, run = height × x. The inclined length is then L = √(height² + run²). Example: height 50 cm at 1:20 needs a run of 10.0 m and an inclined length of about 10.01 m.

What does a 1:12 slope mean?

It means the ramp rises 1 cm for every 12 cm of horizontal run. That equals about 8.33% grade or an angle of roughly 4.8°. The calculator can convert between 1:12, percent grade and degrees instantly.

Is this suitable for ADA-style calculations?

Yes. While the interface uses metres/centimetres and follows common European practice, it fully supports ADA-style ratios like 1:12 and can act as a wheelchair ramp slope calculator. Always check your local code requirements before building.