How much can your rent go up this year in Spain?

Many people look for rent increases in the Spanish Civil Code, or in a supposed "new civil code". They are not there. Annual rent updates for residential tenancies are governed by article 18 of the Urban Leases Act (LAU), as amended by Housing Law 12/2023. The Civil Code does govern other aspects of leases and property sales, but the annual cap on rent is not one of them.

This matters because the terms cited in your contract or in a letter from your landlord should point to the LAU. If someone justifies an increase by citing the Civil Code, they are citing the wrong law.

The rule most tenants do not know: rent is only updated if the contract expressly agreed to it. Article 18.1 of the LAU is literal about this, "in the absence of an express agreement, no rent update shall apply to the contract". If your contract says nothing about review or updates, the rent stays the same for the whole tenancy.

If the contract did agree to updates but did not name an index, the annual variation of the Competitiveness Guarantee Index (IGC) applies. And the update can only happen once a year, on each anniversary of the contract, never mid-year.

This is the distinction that decides your case, and it is not the year your rent goes up but the date the contract was signed. The INE states it explicitly: contracts signed after 26 May 2023 are reviewed on the basis of the IRAV.

Between 2022 and 2024 there was an extraordinary, temporary limit sitting outside the LAU, in article 46 of Royal Decree-Law 6/2022. For anniversaries falling up to 31 December 2023 the increase was referenced to the IGC, and for those falling during 2024 the cap was 3%.

That limit was not extended beyond 31 December 2024. If someone tells you "the legal cap is 3%", they are quoting a rule that is no longer in force. Since 2025, article 18 of the LAU governs again, with the IRAV as the reference limit for contracts signed after 26 May 2023.

The IRAV is the reference index for updating residential rental contracts, which the INE defined as required by Housing Law 12/2023. It is not just another name for the IPC: the INE defines it as the minimum value among the annual variation rate of the IPC, that of core IPC, and the adjusted average annual variation rates of both, corrected by a moderating coefficient.

Because it always takes the lowest of those values, the IRAV tends to sit below the IPC, which is precisely the effect the law intended, avoiding disproportionate increases. The INE publishes it monthly, so it is a figure that changes: check the current official value at the INE on the date of your update rather than trusting a percentage you read somewhere.

The updated rent is only payable from the month following written notice. The notice must state the percentage applied, and if you ask for it, the landlord must attach the corresponding INE certificate. Notice given as a note on the monthly rent receipt is valid.

In other words, an increase communicated verbally, applied retroactively in one go, or given without telling you which percentage was used does not meet what article 18 requires.