The short answer
Inside a dwelling unit, the Ontario Building Code (Table 9.5.5.1) sets minimum door widths of 760 mm (about 30″) for bedrooms, 610 mm (24″) for bathrooms and closets and 810 mm (32″) for entrances and utility rooms, all at least 1980 mm (78″) high. On a barrier-free path, the 2024 Code calls for a clear opening of at least 850 mm, which in practice means a 36″ door.
Minimum door sizes inside a dwelling unit
These come from Table 9.5.5.1 of the Ontario Building Code, Division B, as summarized in a municipal building guide. They’re minimums for the door the opening must fit.
| Location | Minimum width | Smallest standard door that meets it |
|---|---|---|
| Suite entrance or vestibule | 810 mm | 32″ (813 mm) |
| Utility rooms | 810 mm | 32″ |
| Bedrooms | 760 mm | 30″ (762 mm) |
| Other rooms not listed | 760 mm | 30″ |
| Bathrooms and closets | 610 mm | 24″ (610 mm) |
| Height, all of the above | 1980 mm | 80″ (2032 mm) standard |
Standard interior doors are 1-3/8″ thick and 80″ (6′8″) high in widths of 24″, 28″, 30″, 32″ and 36″, so the usual sizes clear these minimums with room to spare.
Accessible and barrier-free openings
For a doorway on a barrier-free path of travel, the 2024 Ontario Building Code (Article 3.8.3.3, in effect for permits from 2025) requires a clear width of at least 850 mm with the door open. The earlier Code used 860 mm. Houses, semis, townhouses and buildings with up to three units are generally exempt from the barrier-free section, so this mostly applies to apartment buildings and their common areas.
Clear width is not the door size. It’s measured with the door open, from the face of the door to the stop on the other side, so the door’s thickness and the stop eat into it. A 36″ door typically leaves about 33-3/4″ (roughly 855 mm) clear, which meets 850 mm. A 34″ door leaves roughly 31-3/4″ (about 805 mm), which doesn’t.
What this means for MLI Select builds
CMHC’s MLI Select awards accessibility points when a share of suites are built accessible or to universal design. Those suites need wider doors along the path through the unit, so plan 36″ doors for their bedrooms and bathrooms and budget them from day one. See doors for MLI Select builds for how we price them.
Quick reference
- Closets and powder rooms: 24″ meets code; 28″ is friendlier.
- Bathrooms: 24″ minimum; 28″ to 30″ is common; 36″ in accessible suites.
- Bedrooms: 30″ minimum; 32″ is common; 36″ in accessible suites.
- Utility and mechanical rooms: 32″ minimum, wider if equipment has to come out.
Sources
- Ontario Building Code Table 9.5.5.1 minimum door sizes, City of Oshawa secondary suite guide
- 2024 Ontario Building Code accessibility changes, City of Brampton report
- Ontario Building Code Article 3.8.3.3 (2012 text), BuildingCode.online
- Accessible doors and clear widths, Construction Canada
Code requirements change and local rules vary. Confirm sizes and clearances with your designer and building department before ordering. We supply doors and trim; we’re not a code consultant.
