Calculate the minimum horizontal run, slope angle, gradient percentage and sloping surface length for a given rise. Standards-aware planning is included for England, Singapore BCA and EU reference use.
Enter a rise and gradient ratio to calculate the ramp.
These values use the same rise entered above. The standards column reflects the selected profile and is a planning aid, not approval. On narrow screens, scroll the table sideways.
| Ratio | Angle | Gradient | Horizontal run | Surface length | Profile indication | Action |
|---|
The non-domestic profile follows Approved Document M, Volume 2. Its ramp table links maximum flight going and rise to the gradient: 10 m at 1:20, 5 m at 1:15 and 2 m at 1:12, with interpolation between those points.
Separate dwelling profiles are included for M4(2) and M4(3). The tool labels these as England because Scotland, Wales and Northern Ireland have separate regulatory guidance.
The BCA profile uses the Code on Accessibility in the Built Environment 2025, version 1.1. Table 5 lists maximum runs of 6 m at 1:12, 9 m at 1:14, 12 m at 1:16, 15 m at 1:20 and 18 m at 1:24.
Ramp width follows the accessible-route table and varies by building use; curved ramps must be 1:16 or gentler. For ratios not expressly listed, the calculator uses the next steeper listed row as a conservative planning estimate and flags the need for confirmation by the Qualified Person or BCA.
EN 17210:2021 sets common functional requirements for an accessible and usable built environment. CEN/TR 17621 provides technical performance criteria, but legal dimensions and enforcement remain country-specific.
The EU profile therefore performs the geometry and highlights design principles, but deliberately does not issue a universal “EU compliant” result.
Horizontal run = vertical rise × ratio denominator
Slope angle = arctan(1 ÷ ratio denominator)
Gradient percent = 100 ÷ ratio denominator
Ramp surface length = √(horizontal run² + vertical rise²)
Where the selected profile gives maximum flight going and/or rise limits, the calculator calculates the flight count required by each applicable limit and uses the larger result. It then equalises the rise and run across the estimated flights. This is a developed-length calculation; a switchback, dog-leg or curved layout has a different plan footprint.
“Horizontal run”, “going” and “plan length” describe the horizontal distance. “Ramp surface length” is the sloping length along the ramp. The angle shown is measured from the horizontal.