Diverse metropolis: Use the calculation tool

Last updated November 9, 2021
Reading time: 2 min

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 450 m2. This applies to both residential and conversion projects (such as converting a commercial building to a residential building) that involve adding at least 1 dwelling.

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)

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 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.

Area 5 is divided into 2 sub-areas: 5A and 5B. Sub-area 5A requires a private family contribution for projects of 50 units or more, but sub-area 5B does not.

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.

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 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.