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Condominium Fee Share Calculator

Permilagem · fundo de reserva · Portugal

Calculate your monthly condominium fee from your unit permillage, including the minimum 10% common reserve fund and optional split of extraordinary works.

By Elijah·UPDATED SEPTEMBER 2026·4 MIN·OFFICIAL SOURCES
KEY FACTS
Base rule
fee = budget × permillage ÷ 1000
Reserve fund
minimum 10% of the share in other expenses
Example
85‰ = 8.5% of the building
Watch out
title or regulations may set special rules
€
PERÍODO DO ORÇAMENTO
Base oficialCódigo Civil arts. 1418.º e 1424.º; DL 268/94 art. 4.º: fundo de reserva obrigatório de pelo menos 10%.
QUOTA MENSAL ESTIMADA
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Peso da fração-
Quota base mensal-
Fundo de reserva-
Prestação de obras-
Parte total nas obras-
Quota anual sem obras-
FÓRMULA-
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How this works

In horizontal property, a condominium fee should not come from a guess. The normal calculation starts from the approved budget and the unit’s relative value, usually written as permillage. This tool turns the default rule into a quick simulation: base share, common reserve fund, yearly amount and any call for works, while keeping the legal exceptions visible.

  1. 1
    Find the unit permillage
    The horizontal-property title sets the relative value of each unit as a percentage or permillage of the whole building. If you have a percentage, multiply it by 10 to get permillage: 8.5% = 85‰.
  2. 2
    Apply the proportion to the approved budget
    The Civil Code default rule is that expenses for the conservation and enjoyment of common parts, and services of common interest, are paid by owners in proportion to their unit value. The tool calculates that share of the monthly or annual budget.
  3. 3
    Add the common reserve fund
    Decree-Law 268/94 makes the common reserve fund mandatory and sets a minimum contribution of 10% of the owner’s share in the other condominium expenses. You can simulate a higher percentage, but the tool does not go below the legal minimum.
  4. 4
    Separate extraordinary works and exceptions
    If the owners’ meeting approved extraordinary works or a one-off cost, you can split that amount by the same permillage and by instalments. Common services can follow a different rule in the regulations, and common parts under exclusive use have their own rules; in those cases, use the minutes and the regulations.

Frequently asked

How do you calculate a condominium fee by permillage?
Divide the unit permillage by 1000 and multiply it by the condominium budget. Example: a €1,200 monthly budget and a unit with 85‰ gives 1,200 × 85 ÷ 1000 = €102 base share, before the common reserve fund or extraordinary works.
Is the common reserve fund mandatory?
Yes. Article 4 of Decree-Law 268/94 requires every condominium to have a common reserve fund for conservation expenses. Each owner contributes at least 10% of their share in the other condominium expenses.
Are all expenses always split by permillage?
No. The default rule is proportional to the unit value, but article 1424 allows a different provision. Certain common services may be split equally or by use if the regulations meet the legal requirements, and common parts under exclusive use may be paid by those who use them.
Is the unit permillage the same as floor area?
Not necessarily. Permillage is the relative value set in the horizontal-property title. It may reflect area, location, use or other factors defined in the title. Use the official value for your unit, not a square-metre estimate.
Does this replace the owners’ meeting minutes?
No. The meeting minutes approving contributions, due dates and expenses are the document to follow and may serve as an enforceable title against non-payment. This tool helps check the proportional calculation before voting, paying or questioning the administrator.
OFFICIAL SOURCES
DISCLAIMER
Informational tool, checked on 29 September 2026 against Civil Code articles 1418 and 1424, Decree-Law 268/94 article 4 and Law 8/2022. It assumes the default legal rule: common expenses split by unit permillage and a minimum common reserve fund of 10% over the other expenses. It does not read the horizontal-property title, regulations, meeting minutes, exclusive-use parts, services split by use/equal parts, penalties, interest, previous debts, insurance or more specific rules. Not legal advice.