The increase depends on when you signed the contract and on what it says. If you signed after 26 May 2023, the limit is the IRAV index published by the INE. And if your contract never expressly agreed to updates, your rent cannot go up at all.
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.
2. No express clause in the contract means no increase
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.
When the contract was signed
How the rent is updated today
After 26 May 2023
Reviewed using the IRAV published by the INE
Before 26 May 2023
Whatever was agreed; with no index agreed, the IGC, and never above the IPC
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 If someone tells you "the legal cap is 3%", they are quoting a rule that is no longer in force.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.
5. What the IRAV is, and why it usually sits below the IPC
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.
It depends on whether the same contract continues or a new one is signed. Once the five-year mandatory extension is over — seven if the landlord is a company — and neither side gives notice in time that it will not renew, the contract extends year by year for up to three more years (article 10 of the LAU). It is the same contract and what you agreed still applies, so the rent only rises through the update clause you signed, once a year and within the same limit.
What changes the figure is a new contract. If the landlord tells you at least four months in advance that they will not renew, they can offer to continue at a different rent, and outside stressed areas that rent is freely agreed: the law puts no cap on the starting price of a new contract.
In a declared stressed residential market area, there is one. The rent of the new contract cannot exceed the last rent the same home had in the previous five years, with its annual update applied, and only up to 10% more can be added in specific cases, such as recent renovation or energy-efficiency works. If the landlord is a large holder, the limit is the one set by the reference price index system. In those areas, when the mandatory or tacit extension ends you can also request an extraordinary extension of up to three years on the same terms, which the landlord must accept save for exceptions.
Royal Decree-Law 8/2026 was in force between 22 March and 29 April 2026. It capped the rent increase at 2% for residential leases whose anniversary fell in that period, absent a fresh agreement between the parties, and the cap was mandatory whenever the landlord was a large-scale holder ("gran tenedor"). Congress refused to ratify it on 28 April 2026, and the derogation resolution was published in the BOE on 30 April 2026, the date from which the decree-law stopped being in force.
If your update fell within those dates, the 2% cap applied to it while the rule was in force. Neither the decree-law nor the resolution that repealed it says explicitly what happens to updates already made at 2% during that period; the general rule is that a failed ratification has no retroactive effect, so those updates should stand, but it is worth confirming with a professional if your case falls right on that margin.
Frequently asked questions
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