What Wheelchair Ramp Gradient Do I Need?

Gradient Requirements (Part M)

• 1:20 (5%): Preferred for all ramps. Maximum going 10m per flight (500mm rise) before a landing is required
• 1:15 (6.7%): Acceptable for going up to 5m
• 1:12 (8.3%): Maximum steepness, going no more than 2m

Practical Example

For a 150mm step at a front door:

• At 1:12: ramp length = 150 × 12 = 1,800mm (1.8m)
• At 1:15: ramp length = 150 × 15 = 2,250mm (2.25m)
• At 1:20: ramp length = 150 × 20 = 3,000mm (3m)

Key Design Requirements

• Minimum width: 1,500mm between walls, upstands or kerbs for non-domestic buildings (AD M Vol 2). Dwelling ramps under Vol 1 range from 900mm to 1,200mm depending on category
• Handrails: Both sides, 900–1,000mm high. Extend 300mm beyond top and bottom
• Level landings: 1,200mm long minimum (at the full ramp width), clear of door swings, at top and bottom
• Rest platforms: Every 5m going (at 1:15) or 10m going (at 1:20)
• Kerb/upstand: 100mm minimum on open sides to prevent wheels slipping off
• Surface: Non-slip, contrasting colour nosing at top and bottom

Crossfall

Approved Document M gives ramp landings a maximum crossfall of 1:40 (2.5%) for drainage. Keep the ramp surface itself as close to level across its width as you can: steeper crossfalls make it difficult for wheelchair users to maintain a straight path.

Important Note

The figures above are from Approved Document M Volume 2, which covers buildings other than dwellings. A private dwelling entrance ramp falls under Volume 1 (the M4 categories) instead, with different width and gradient limits: wheelchair-user dwellings (M4(3)) cap the gradient at 1:15, so 1:12 is not permitted there. Always consult Building Control for specific projects, especially for commercial or public buildings where BS 8300 may impose stricter requirements. Individual circumstances may require bespoke solutions.