The comparative factor is an official coefficient published yearly by Quebec’s Ministry of Municipal Affairs and Housing (MAMH). It transforms your municipal assessment into an estimate of actual market value at the time the factor is calculated. This article focuses exclusively on the calculation method and borough table — not on the conceptual comparison between assessment and market value (see our dedicated article).
1. The Official MAMH Formula
Estimated market value = Municipal assessment × Comparative factor
This formula is used by:
- Financial institutions to support mortgage loan analysis
- The municipal court in assessment disputes
- Tax specialists for welcome tax calculations (which uses the higher of: purchase price or assessment x factor)
- The administrative tribunal of Quebec in expropriation cases
2. Montreal Triennial Roll: 2023-2025 vs 2026-2028
Quebec’s property assessment system operates on triennial rolls. The 2023-2025 roll covered fiscal years 2023, 2024 and 2025 — based on market values as of July 1, 2021. The new 2026-2028 roll takes effect January 1, 2026 and is based on values as of July 1, 2024.
⚠️ Important: the comparative factors published by MAMH apply to the current roll. For 2026, use the factors of the new 2026-2028 roll (published by the City of Montreal in the first quarter).
3. Indicative Factor Table by Borough
The table below gives typical observed ranges for the 19 Montreal boroughs under the 2023-2025 roll. Exact 2026 values must be verified on montreal.ca or with the MAMH.
| Borough | Typical Range 2023-2025 | Trend |
|---|---|---|
| Ahuntsic-Cartierville | 1.15 — 1.30 | Moderate |
| Anjou | 1.10 — 1.25 | Stable |
| Côte-des-Neiges–Notre-Dame-de-Grâce | 1.20 — 1.35 | Moderate |
| Lachine | 1.15 — 1.30 | Moderate |
| LaSalle | 1.10 — 1.25 | Stable |
| Le Plateau-Mont-Royal | 1.25 — 1.40 | Strong |
| Le Sud-Ouest | 1.30 — 1.50 | Very strong |
| Mercier–Hochelaga-Maisonneuve | 1.20 — 1.40 | Strong |
| Montréal-Nord | 1.15 — 1.30 | Moderate |
| Outremont | 1.20 — 1.35 | Moderate |
| Rivière-des-Prairies–Pointe-aux-Trembles | 1.10 — 1.25 | Stable |
| Rosemont–La Petite-Patrie | 1.25 — 1.40 | Strong |
| Saint-Laurent | 1.15 — 1.30 | Moderate |
| Saint-Léonard | 1.15 — 1.30 | Moderate |
| Verdun | 1.30 — 1.50 | Very strong |
| Ville-Marie | 1.20 — 1.35 | Moderate |
| Villeray–Saint-Michel–Parc-Extension | 1.25 — 1.40 | Strong |
Note: ranges above are approximations based on the 2023-2025 roll (values as of July 1, 2021). Exact 2026 factors from the new roll are available from the City of Montreal and the MAMH.
4. Concrete Calculation Example
Case: Single-family home in Rosemont–La Petite-Patrie
Municipal assessment: $580,000
Estimated comparative factor: 1.32 (median of range)
Estimated market value: 580,000 × 1.32 = $765,600
This estimate corresponds to a borough average. To validate, compare with recent sales on the same street or building. Our estimator uses more than 11,000 recent sales in CourtiConnect’s database to refine this calculation by property type, area and condition.
5. Method Limitations
The comparative factor is an average coefficient that does not account for:
- Major renovations completed after the assessment date
- Overall condition, view, floor (for a condo), exposure
- Sub-borough variations (e.g.: Saint-Henri vs Pointe-Saint-Charles within Le Sud-Ouest)
- Market movement between the assessment date and today
For accurate estimation, cross the comparative factor with an analysis of recent comparables (last 12 months) on similar properties.
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