"Why do I pay more than my neighbor, if the apartment has the same number of bedrooms?" It's the most common question about condominium dues — and the answer lies in a term most owners have heard but few can explain: ownership share (called permilagem in Portugal, expressed in per-mille).
What Ownership Share Is
Ownership share is each unit's proportional stake in the building's total value, expressed in per-mille (‰), always adding up to 1000‰ across the whole condominium. It's set out in the founding deed of the horizontal-property regime, based on each unit's relative value within the whole — not the number of bedrooms, nor the opinion of whoever lives there.
This means a larger apartment, with better sun exposure or a higher floor (in buildings with no elevator, for instance, this can weigh the other way), typically has a higher ownership share — and pays proportionally more toward shared costs.
The Formula
Unit's dues = (Unit's ownership share ÷ 1000) × Total costs to be split
Practical example: a condominium with €12,000 in annual shared expenses, and a unit with an 85‰ ownership share:
Unit's annual dues = (85 ÷ 1000) × €12,000 = €1,020/year (€85/month)
This is the legally preferred method for most shared costs — it reflects each owner's real proportion of the property's value, and it's the default criterion the law assumes unless otherwise resolved.
When Ownership Share Isn't the Only Method
Not every cost has to follow strict ownership share — the law allows different criteria for specific expenses, as long as they're properly resolved:
Equal shares — for costs that benefit every owner equally, regardless of the unit's value (e.g., stairwell cleaning, common entrance lighting). Using this method for a cost that would normally be split by ownership share requires assembly approval — it's not a unilateral decision by the administrator.
Manual/specific splitting — for particular cases (e.g., elevator maintenance charged only to the units that use it, if the building has ground-floor units with their own separate entrance), defined case by case and also subject to a resolution.
Common Mistakes When Calculating Dues
- Using the number of units instead of ownership share — splitting the total by "how many apartments there are" completely ignores the legal proportionality and produces incorrect dues
- Applying equal shares to structural maintenance costs without that resolution existing — even if it "feels fairer" informally, without assembly approval it's a departure from the default legal criterion
- Not separating the Common Reserve Fund rate from the current dues amount — the reserve fund (minimum 10% of the ownership share) should be visible separately, not hidden inside the total value
- Not updating the ownership share after an approved structural change (e.g., a unit gains an annex that alters its relative value) — the ownership share only changes via notarial deed, but ignoring a pending update perpetuates an outdated calculation
How to Simplify This in Practice
Manually calculating the ownership-share split for dozens of units, every month, with the reserve-fund rate added on top and potentially a different criterion for specific costs, is exactly the kind of task where a formula error in a spreadsheet cell goes unnoticed for months. ActiasGest automatically calculates the split by ownership share, equal shares, or manual method, with the reserve-fund rate already included, generating each unit's exact dues amount without manual recalculation.
Learn more → actias-gest.solid-ai.net