Rent Update Coefficient for Tenants in Portugal

Rent & updates (index/coefficient, caps) 3 min read · published September 11, 2025

Managing rent increases is a common concern for tenants in Portugal. The rent update coefficient defines when and how much a landlord can raise the rent, and it is subject to legal rules, deadlines and limits that protect both parties. This guide explains in simple terms what the coefficient is, how it is calculated, the limits provided by law and the practical steps a tenant can take if they disagree with an increase. It includes guidance on documents, deadlines for contesting and official contacts where you can request information or file a complaint in Portugal. The language is clear and aimed at people living in rental situations who are not lawyers.

O que é o coeficiente de atualização

The rent update coefficient is an indicator value that allows adjusting the rent amount over time to reflect inflation or economic variations. These updates are regulated by applicable legislation and normally can only occur as provided in the lease agreement or by law.

In many cases, only increases provided in the contract or by law are valid.

Como se calcula

The calculation depends on the method provided in the contract or by applicable legal rule. Usually a reference index (for example, price indices) is used multiplied by a coefficient applicable to the relevant period. Ask the landlord for the formula used and the documents that support the increase.

  • Request a written demonstration of the rent calculation, with periods and detailed amounts.
  • Check if the index applied is the one provided in the contract or in the law.
  • Keep receipts and communications to create evidence in case of a dispute.
Detailed documentation increases your chances of success in a dispute.

Limites e prazos

There are legal limits and deadlines to consider: the increase may be subject to percentage caps, minimum periodicity and rules on notification to the tenant. Check the contract and, if in doubt, ask the landlord for clarification in writing.

  • Observe notification deadlines provided in the contract or by law.
  • Verify if a percentage limit applies to the increase.
  • Record the date of receipt of the notification and keep copies.
Respond to legal notices within deadlines to avoid losing rights.

O que fazer se discordar

If you disagree with the increase, request the landlord's detailed formula in writing and submit a formal objection by registered mail or email with read confirmation. You can request mediation or file a complaint at the Balcão do Arrendatário e do Senhorio; in some cases it is possible to go to civil court. Whenever you refer to the law, consult the NRAU and the applicable statutes to know which limits apply.[1] For procedures and forms, use the Citius services.[2]

Keep all communications and receipts related to the rent.

Perguntas Frequentes

Can the landlord increase the rent without notice?
Usually not; the increase must respect the contract and legal notification deadlines. If there is no valid notice, the tenant can contest the increase.
Can I refuse the increase and stay in the property?
Refusing without action can create conflict. The tenant can negotiate, request mediation or file an objection with the Balcão do Arrendatário e do Senhorio or the court.
What evidence should I keep to contest an increase?
Rent receipts, written notices, messages with the landlord and any calculation that proves the applied increase.

Como Proceder

  1. Request from the landlord the written explanation of the increase calculation and the reference to the index used.
  2. Formally notify your disagreement by registered letter or email with read confirmation.
  3. Gather evidence: receipts, communications and photographs, if relevant.
  4. Request information or mediation at the Balcão do Arrendatário e do Senhorio or consult a lawyer if necessary.
  5. If there is a legal violation, file a complaint or legal action within the applicable deadlines.

Principais Conclusões

  • Always request a written demonstration of the rent increase calculation.
  • Keep all documents and communications as evidence.
  • Use official services for clarification and mediation before going to court.

Ajuda e Recursos


  1. [1] NRAU — Lei n.º 6/2006 (dre.pt)
  2. [2] Balcão do Arrendatário e do Senhorio (Citius)
Bob Jones
Bob Jones

Editor & Researcher, Tenant Rights Portugal

Bob writes and reviews tenant law content for various regions. They’re passionate about housing justice and simplifying legal protections for tenants everywhere.