Diverse metropolis: Use the calculation tool
The By-law for a Diverse Metropolis sets out various obligations around housing. Real estate developers must contribute to Montréal’s supply of social, affordable and family housing. Here’s how to use our contribution calculation tool.
A contribution is required for all projects whose residential area is greater than the threshold set in the by-law. This applies to projects involving the addition of at least 1 dwelling unit, whether it is a new construction or the conversion of an existing building.
Social, affordable and family housing contributions depend on two factors:
- Project location (value area, affordable housing zone)
- Project scope (residential area, number of housing units)
To take account of the economic context and promote housing starts, certain temporary rules are in force until December 31, 2026:
- The regulatory threshold set by the by-law is raised from 450 m² to 1800 m².
- The conversion of office use to dwelling units in area 1 of the by-law (corresponding approximately to the downtown) is exempted.
How to use the tool
There are two ways to search: by lot number and by area.
Search by lot number
If you know the lot number(s) where the project will be built, this is the most effective search method. Enter one of the lot numbers and the tool will determine the area and zone where the lot is located.
Then, enter the total residential area and the number of dwelling units. The tool will calculate the required contribution for the three components.
Search by area
If you don’t know the lot number, you can select the value area in which the project will be located.
Areas
Areas are numbered from 1 to 5 and are used to calculate social, family and affordable housing contributions. If the project’s location is in more than one value area, the contribution is calculated according to the area for which the amount is higher.
Affordable housing zones
Some areas include affordable housing zones. In these zones, the affordable housing contribution is a percentage of the project. There are of two types of zones:
- Affordable zone 1: 10 per cent of the project
- Affordable zone 2: 20 per cent of the project
Other zones will be added over time as the urban development plan is amended. Find out more.
Outside these zones, only projects with an area greater than 4,500 m2 are subject to the affordable housing contribution, with the exception of projects for which an agreement has been reached under the by-law during the period from March 20, 2024 to December 31, 2026.
Project characteristics
Once you have entered the area or lot number, you must provide the residential area and number of units for your project.
Residential area is the total floor area, including common areas (e.g., mezzanines, stairways, elevators and entranceways). It does not include commercial space, parking lots and parts of the basement that are not occupied by dwellings or parts of dwellings. The area of a possible social housing phase planned for the site must, however, be excluded from the calculation.
For the period from March 20, 2024 to December 31, 2026, a conversion of office use to dwelling units in area 1 of the by-law (corresponding approximately to the downtown) will no longer be considered as an addition to the residential area.
The number of dwellings is used to calculate the family housing contribution. Only residential projects with at least 50 dwellings must contribute to private family housing.
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