Canada guidance
Canada ramp requirements: NBC, OBC and AODA
Canada has no single ramp number. The building codes use 1:12 for barrier-free building ramps; Ontario’s AODA uses 1:15 for ramps on exterior paths in public spaces. This page maps the instruments, explains the split, and turns your rise into both ramp runs.
General information, a planning aid, not certification. Ramp rules vary by province, territory and municipality. Always confirm with your local building department or municipal authority before you build.
Where these rules apply
A ramp in Canada can be governed by a building code, by a separateaccessibility statute (Ontario’s AODA), or by both, depending on what the ramp serves and which organization owns it. The building code is adopted province by province; the AODA applies in Ontario. This page keeps the two apart instead of merging them into one “Canadian” number.
Planning aid, not certification. This page summarises published requirements in plain English; it is not legal or design advice, and it is not a building-code consultation. The authority that applies to your project, your provincial code edition and your municipality, decides what compliance means. Check with that authority before building.
The quoted instrument numbers are listed in the sources section with the dates they were checked. Standards are updated over time, where a code or regulation references a standard, the cited (or latest) edition applies.
Canadian ramp calculator: 1:12 and 1:15
Enter the total rise, the vertical distance the ramp must climb, and compare the two main paths: a building-code ramp (NBC/OBC, maximum 1:12) and anAODA exterior-path ramp (maximum 1:15). The calculator shows each run length and how many intermediate landings a straight run needs at 9 m intervals. Top and bottom landings come on top. Only published slope limits are used, nothing is interpolated.
Ramp plan
A 1,000 mm rise works out to about 12 m of ramp at the building-code maximum of 1:12, or about 15 m at the AODA exterior-path maximum of 1:15. Top and bottom landings are required for both; intermediate landings at 9 m intervals: 1 (straight run) at 1:12, 1 (straight run) at 1:15.
| Instrument | Max slope | Ramp run for your rise | Intermediate landings (≤9 m apart) |
|---|---|---|---|
| Building codes, NBC 2020 / OBC 2024 | 1:12 | ≈12 m | 1 (straight run) |
| AODA exterior paths, O. Reg. 191/11 s. 80.24 | 1:15 | ≈15 m | 1 (straight run) |
How these numbers are made: run = rise × slope ratio (12 m at 1:12 and 15 m at 1:15 for a 1,000 mm rise). Intermediate landings are counted so that no stretch of a straight run exceeds 9 m, the top and bottom landings are additional. A turn adds a landing at the change of direction; a longer linear run adds an extra landing each time it passes another 9 m. Landings themselves add length beyond the run. This calculator assumes a straight run and level landings; it does not size door maneuvering areas, handrail extensions, edge protection, drainage or guards.
Building-code ramps (1:12)
- NBC 2020: uniform slope not more than 1 in 12; clear width at least 1,000 mm; level area at least 1,700 × 1,700 mm at a doorway (top, bottom and intermediate levels of a ramp leading to a door); level areas at least 1,350 mm long at intervals not more than 9 m and at abrupt changes of direction; handrails 865–965 mm (Art. 3.8.3.5, and 3.4.6.7 for general ramps, industrial occupancies are the exception).
- OBC 2024 (Ontario): maximum gradient 1 in 12; level areas at least 1,700 × 1,700 mm at the top and bottom; level areas at least 1,700 mm long at intervals not more than 9 m and at changes of direction of 90° or more; width at least 1,000 mm between handrails (Art. 3.8.3.4). Where a door is in the ramp, the level area extends 600 mm/300 mm past the latch side depending on the door swing.
AODA exterior-path ramps (1:15)
- O. Reg. 191/11, s. 80.24: maximum running slope not more than 1:15; minimum clear width 900 mm; landings at the top and bottom, at abrupt changes of direction, and at horizontal intervals not greater than 9 m apart; landings at least 1,670 × 1,670 mm at the top, bottom and turns (in-line landings at least 1,670 mm long and at least as wide as the ramp); cross slope not steeper than 1:50; handrails on both sides 865–965 mm with 300 mm extensions; edge protection (a curb at least 50 mm, or a barrier reaching within 50 mm of the surface).
This is a summary of the ramp provisions only, surfaces, illumination and other rules also apply. Verify every figure against the source documents and your local authority.
The instruments at a glance
| Instrument | Applies to | Max running slope | Clear width | Landings / level areas |
|---|---|---|---|---|
| NBC 2020 (national model code) | Barrier-free ramps in buildings, in the provinces and territories that adopt it, the common baseline | 1 in 12 | ≥1,000 mm | 1,700 × 1,700 mm at doorways; ≥1,350 mm long at ≤9 m intervals |
| OBC 2024 (Ontario buildings) | Building construction in Ontario (Building Code Act, 1992) | 1 in 12 | ≥1,000 mm between handrails | 1,700 × 1,700 mm at top and bottom; ≥1,700 mm long at ≤9 m intervals |
| AODA Design of Public Spaces (Ontario) | Exterior paths of travel, ramps on sidewalks, plazas, parks and similar public spaces | 1:15 | ≥900 mm | 1,670 × 1,670 mm at top, bottom and turns; ≤9 m intervals |
Different instruments, different scopes: the building codes are about buildings; Ontario’s AODA is about exterior public spaces. Compare the landings column too. It is not one number across Canada.
Buildings vs exterior public spaces: the split nobody explains
The most common Canadian ramp mix-up is using one slope everywhere. In Ontario, two separate instruments cover ramps, and they do not share a number:
- The Ontario Building Code (O. Reg. 163/24 under the Building Code Act, 1992, enforced through permits and inspections) sets 1 in 12 as the maximum gradient for barrier-free ramps as part of building construction. Article3.8.3.4: note that the NBC’s equivalent article is 3.8.3.5; Ontario renumbers.
- The AODA (Accessibility for Ontarians with Disabilities Act, 2005; its Design of Public Spaces Standard, O. Reg. 191/11, Part IV.1) sets ramp rules forexterior paths of travel when obligated organizations build or redevelop public spaces. Section 80.24 is blunt about the slope:“The ramp must have a maximum running slope of no more than 1:15.”
So the answer to “what slope does Ontario require?” is “it depends on what the ramp is part of”, a building or an exterior path. The two numbers are not interchangeable, and picking the convenient one is how projects get re-done. If a project includes both a building ramp and exterior path ramps, each element is checked against the instrument that governs it; confirm applicability with your municipality before you build.
Quick test: a ramp that helps people travel along a sidewalk, trail or plaza in a public space is likely an AODA exterior path (1:15). A ramp into or inside a building is a building-code ramp (1:12). A ramp on private residential property follows whatever your province and municipality apply to housing, which is not necessarily either number above.
Building codes across Canada
The National Building Code of Canada (NBC) is a national model code published by the National Research Council. It becomes the law through each province’s and territory’s own adoption and amendments. The practical consequences for a ramp:
- Edition matters. Older guides and some web pages still quote 1,500 × 1,500 mm landings from pre-2020 code editions. The NBC 2020 figures on this page supersede those for jurisdictions on the 2020 model.
- Numbering differs. Article 3.8.3.5 in the NBC is 3.8.3.4 in the 2024 OBC. Search for the provision by subject, not by number, when you check a local code.
- Local amendments are normal. Alberta’s current code, for example, is based on NBC 2020 with provincial amendments (NBC(AE) 2023). Ontario publishes its own OBC. Check the edition in force where you are building.
- Municipalities can add more. Cities often apply stricter accessibility standards to their own facilities and public realm projects than either the building code or the AODA minimums. Your municipality is the practical starting point.
What about CSA/ASC B651?
CSA/ASC B651, Accessible design for the built environment, is the National Standard of Canada that many codes, regulations and designers lean on for accessibility detail. Accessibility Standards Canada notes it is “referenced in the National Building Code and other legislation across Canada.” The current edition is CSA/ASC B651:23: the sixth edition, published January 2023, superseding B651-18.
Key ramp values in B651:23 (checked against the CSA-hosted copy of the standard):
- Running slope between 1:12 (8.33%) and 1:20 (5%), with level landings at horizontal distances of not more than 9,000 mm; the standard notes that slopes between 1:20 and 1:15 are preferred.
- Clear width at least 1,200 mm; cross slope not steeper than 1:50.
- Landings at least 1,700 mm long, at the top and bottom of each ramp and at all changes of direction; at least 2,100 × 2,100 mm at doorways serving an accessible route and for passing spaces.
- Exterior ramps follow the same slope and landing rules, with handrails required where the vertical rise is more than 250 mm.
B651 is a standard, not a building code: it binds your project when a code, regulation, tender or designer names it. If your authority cites B651, confirm the edition it references, B651-18 and B651:23 differ in places (dimensions were updated in 2023).
Sources
Each figure on this page was checked against the publication below, on the date shown.
- National Building Code of Canada 2020, free copy in the NRC Publications Archive (DOI 10.4224/w324-hv93): ramp provisions Art. 3.4.6.7 and 3.8.3.5. Checked 26 September 2026.
- Ontario Building Code 2024 (O. Reg. 163/24 under the Building Code Act, 1992, e-Laws); ramp provisions Art. 3.8.3.4, read from the official 2024 OBC Compendium (Publications Ontario). Checked 26 September 2026.
- AODA Integrated Accessibility Standards, O. Reg. 191/11, Part IV.1 Design of Public Spaces, s. 80.24 (e-Laws): read from the current consolidation, checked 6 October 2026.
- CSA/ASC B651:23, Accessible design for the built environment, CSA Group store page; ramp values (Clauses 5.5 and 8.2.7) read from the CSA-hosted digital copy of the standard, checked 6 October 2026.
- Accessibility Standards Canada, CSA/ASC B651 page: “referenced in the National Building Code and other legislation across Canada.” Checked 6 October 2026.
Summaries only: the full requirements, definitions and cross-references (fire, structural, egress) still apply, and amending instruments may have changed a detail after our check dates. This page is not a substitute for the codes, the standard, or your building department. In the US? See the ADA ramp requirements guide. In the UK? See the Approved Document M guide.