UK ramp calculator, Approved Document M
Enter the rise and the gradient and this returns the going, the surface length, the longest flight allowed, how many flights and landings you need, and the minimum width. It asks what the ramp is serving first, because the approach to a house, a ramp inside a house and a ramp at any other building follow three different sets of rules, and most published guidance only gives one of them.
Three sets of ramp rules, not one
This is the thing to get right before any number matters. Approved Document M comes in two volumes. Volume 1 covers dwellings and Volume 2 covers buildings other than dwellings. Approved Document K then covers ramps that form part of a building, a house included. Where Part M and Part K both apply to the approach to a house, Volume 1 gives Part M precedence (paragraph 0.14). The three do not agree on ramps, and almost every UK ramp page publishes the Volume 2 figures without saying which building they apply to.
| Approach to a dwelling, AD M Volume 1, M4(1) | Inside a dwelling, AD K | Other buildings, AD M Volume 2 | |
|---|---|---|---|
| Gradient and flight length | 1:15 or shallower, up to 10m. 1:12, up to 5m. | 1:20 up to 10m. 1:15 up to 5m. 1:12 up to 2m. | The same as AD K. |
| Minimum width | 900mm | None set | 1500mm |
| Handrails | None required | None up to 600mm of rise. Above that, one side or both under 1000mm wide, both sides at 1000mm or wider, 900mm to 1000mm high. | Both sides, 900mm to 1000mm above the ramp. |
| Landings | 1200mm at the top, the bottom and between flights, clear of any door swing. | At least as long as the ramp is wide. | 1200mm at the top and the bottom, 1500mm between flights. |
| Maximum rise per flight | Set by the flight length: about 667mm at 1:15 and 417mm at 1:12. | Set by the flight length: 500mm at 1:20, 333mm at 1:15, 166mm at 1:12. | 500mm |
A ramp inside the house
A ramp inside a dwelling, between two floor levels in an extension for example, is not an approach route, so Volume 1 does not set its limits. Approved Document K does. Its paragraphs 2.3 and 2.8 apply to all buildings, dwellings included: any floor at 1:20 or steeper is designed as a ramp, the same gradient and flight length limits as Volume 2 apply, nothing is steeper than 1:12, there is 2m of clear headroom, and every landing is at least as long as the ramp is wide.
Handrails come from paragraph 2.12. A ramp rising 600mm or less needs none. Above that, a ramp under 1000mm wide needs a handrail on one side or both, and one 1000mm wide or more needs them on both sides, with the top of the rail 900mm to 1000mm above the ramp. Landings follow the stair rules, under paragraph 2.14.
M4(1), M4(2) and M4(3)
Volume 1 contains three optional standards for new dwellings and only one of them applies by default.
- M4(1) Visitable dwellings. The baseline. It applies to new dwellings automatically.
- M4(2) Accessible and adaptable dwellings. Applies only where a planning condition imposes it.
- M4(3) Wheelchair user dwellings. Also only through a planning condition.
M4(2) and M4(3) are not things you opt into and not things that apply because a building sounds like it should be accessible. They are triggered by the planning permission for the site. Check the decision notice before designing to either, and check it before assuming neither applies.
Where one does apply, the ramp changes. M4(2) keeps every flight between 1:20 and 1:12 on the same length curve as Volume 2, at 900mm wide on a private approach and 1200mm on a communal one, and a communal ramp rising 300mm or more needs a stepped route as well. M4(3) holds the gradient between 1:20 and 1:15 and needs 1200mm.
Landings, and why a long ramp gets expensive fast
A ramp is not one continuous slope. Each flight is capped, and between flights you need a landing, level or no steeper than 1:60 along it and 1:40 across. Under Volume 2 that is 1500mm for an intermediate landing and 1200mm at the top and the bottom, and none of it counts toward the going.
This is why ramps take so much more room than people expect. A 900mm rise at 1:12 is 10.8 metres of going. Under Volume 2 that gradient caps a flight at 2 metres, so you need six flights of 1.8 metres and five intermediate landings: 18.3 metres on plan. Run the same rise at 1:20 and it is two flights of 9 metres and one landing, 19.5 metres. Neither is the shortest. Three flights at about 1:14 come to about 15.9 metres. Add 1.2 metres of landing at the top and the bottom of each.
Three or more flights also brings in passing places, and if every intermediate landing has to be one, the 1:12 layout grows to 19.8 metres and the three flight layout to 16.5. The calculator works the layout out for the gradient you enter and suggests the shortest one.
What else Volume 2 asks for
- Steps as well. A ramp rising more than 300mm needs clearly signposted steps alongside it.
- Passing places. Where there is no clear line of sight along the ramp, or it has three or more flights, intermediate landings of at least 1800mm by 1800mm.
- Landing falls. No steeper than 1:60 along a landing and 1:40 across it.
- A kerb. At least 100mm high on the open side of any ramp or landing, contrasting visually with it.
- Handrails. On both sides, 900mm to 1000mm above the ramp and 900mm to 1100mm above landings, extending at least 300mm past the top and bottom, with a second lower rail at 600mm where one is provided alongside full height guarding.
A ramp is not always the answer
Under Volume 2, a total rise over 2 metres means a ramp on its own is not enough and a lift or another means of access has to be provided as well. On a constrained site it is worth testing that number early, because it can change the whole approach rather than just the ramp.
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Start free with Built SimpleFrequently Asked Questions
What is the maximum ramp gradient under UK building regulations? 1:12, and only for a short flight. Approved Document M Volume 2 and Approved Document K allow 1:12 for up to 2 metres, 1:15 for up to 5 metres and 1:20 for up to 10 metres. On the approach to a dwelling, Volume 1 allows 1:12 up to 5 metres and 1:15 up to 10 metres.
How wide does a wheelchair ramp have to be in the UK? 1500mm of surface width under Volume 2 for buildings other than dwellings. On the approach to a dwelling Volume 1 asks for 900mm, or 1200mm on a communal approach under M4(2) and on any approach under M4(3). Approved Document K sets no minimum width for a ramp inside a house.
Do I need handrails on a ramp at a house? It depends where the ramp is. On the approach, the M4(1) standard in Volume 1 sets no handrail requirement. For a ramp inside the house, Approved Document K asks for none at 600mm of rise or less, and above that for a handrail on one side or both of a ramp under 1000mm wide and on both sides of one 1000mm wide or more, 900mm to 1000mm above the ramp. Volume 2, for other buildings, requires handrails on both sides.
How long can a ramp be before it needs a landing? It depends on the gradient and on which rules apply. Under Volume 2 and Approved Document K a 1:12 flight caps at 2 metres, 1:15 at 5 metres and 1:20 at 10 metres, and Volume 2 intermediate landings are 1500mm long. On the approach to a dwelling a flight can run 5 metres at 1:12 or 10 metres at 1:15, with 1200mm landings. No landing counts toward the going.
Does M4(2) apply to my house? Only if a planning condition imposes it. M4(1) is the standard that applies to new dwellings by default. M4(2) and M4(3) are optional standards that come through planning, so check the decision notice.
Related calculators and guides
Sources
- Approved Document M, Volume 1, Dwellings, 2015 edition incorporating 2016 amendments, HM Government. Paragraphs 0.14, 1.7, 2.8 to 2.10 and 3.10.
- Approved Document M, Volume 2, Buildings other than dwellings, 2015 edition incorporating 2020 and 2024 amendments, HM Government. Paragraphs 1.26 and 1.37.
- Approved Document K, Protection from falling, collision and impact, 2013 edition, HM Government. Paragraphs 2.3, 2.8, 2.12 and 2.14.
- Building Regulations 2010, Schedule 1, Parts K and M. Approved Documents are free under the Open Government Licence.
