A flat let for 900 euros a month under a lease signed in October 2025 can rise in October 2026 to 922.23 euros at most, even though the August CPI was 4.3 %. Residential leases signed on or after 26 May 2023 are capped by the INE’s IRAV index, which was 2.47 % in August. The same rent under an older lease, signed before that date and last updated in October 2025, could rise to 938.70 euros if the lease provides for a CPI update.
That difference causes more disputes between landlords and tenants than anything else this year, and the calculator applies it for you. It works just as well for child or spousal maintenance paid after a divorce, and for any amount a contract says must be updated with the Spanish CPI.
How much a rent can rise
A residential rent in Spain is only updated if the lease says so, once a year on each anniversary, and the increase can never exceed the CPI, under article 18 of the Urban Leases Act. For leases signed on or after 26 May 2023 there is a further cap, the Housing Rental Reference Index or IRAV, which the INE has published monthly since November 2024 and which tends to sit well below the CPI when inflation rises. To apply it, the calculator asks for the date the lease was signed.
Between 31 March 2022 and 31 December 2024 there were extraordinary caps. Without a new agreement with the tenant, updates in 2022 and 2023 could not exceed the change in the Competitiveness Guarantee Index, and those in 2024 could not exceed 3 %. If you were charged more in those years, the difference can be claimed.
The increase is not automatic. The landlord must notify it in writing with the percentage applied, a note on the receipt is enough, and the new rent is due from the following month. For shops, offices and warehouses the rent is updated as the lease says, without the IRAV cap. If the problem is a tenant who does not pay, what comes next is on the evictions page.
How much maintenance your ex should be paying
Child maintenance and spousal maintenance are updated as the judgment or the settlement agreement says, almost always yearly with the CPI. A child maintenance payment of 300 euros set in January 2022, updated every January with the December CPI, develops like this.
| Update | Previous December CPI | Monthly payment |
|---|---|---|
| January 2023 | 5.7 % | 317.10 € |
| January 2024 | 3.1 % | 326.93 € |
| January 2025 | 2.8 % | 336.08 € |
| January 2026 | 2.9 % | 345.83 € |
If the payer kept paying the original 300 euros, by the end of September 2026 they owe 1,373.79 euros, the sum of what was underpaid each month. The update is due even if nobody claims it, and the arrears are claimed by enforcing the judgment before the court that issued it. Anything older than five years can no longer be claimed, under article 1966 of the Civil Code, so waiting has a cost.
The calculator does this sum if you choose the maintenance option. It asks for the amount set, when it was set, the month it is updated and which month’s CPI applies, and what has been paid each month, and it returns the year-by-year table, today’s amount and the arrears, with those over five years old shown separately. If what was paid changed from month to month, we work out the exact figure with the payment records in front of us.
How it calculates
It divides the Spanish national general CPI index for the final month by the index for the starting month, rounds the result to three decimals and multiplies it by the amount. That is the method of the INE’s own calculator, and over twelve months it gives exactly the annual rate the INE publishes. The indices go back to January 2002, and when the page opens it asks the INE for any months published since, so the latest figure is there without anyone having to update the website. For residential leases signed on or after 26 May 2023 it compares the result with the IRAV for the same month and gives you the maximum amount. For maintenance it applies each year the annual CPI change published by the INE, which since 2003 matches that ratio and is available back to 1962, so it also works for older judgments.
What it does not calculate
It does not apply indices other than the national general CPI, such as the Galician CPI or a specific spending group, if your contract chooses one. Nor does it cover old-rent leases from before 1995, which have their own rules, or the legal caps when several years of a lease are updated at once, because each year is counted separately. We review those cases with you, in English. You can call us on +34 677 841 007, and the rest of our work is on the civil law and debt recovery pages.
Frequently asked questions
How much can rent go up in Spain in 2026?
It depends on when the lease was signed. For residential leases signed on or after 26 May 2023 the annual increase cannot exceed the IRAV published by the INE, which was 2.47 % in August 2026. For older leases the cap is the CPI, 4.3 % in August. In both cases rent only rises if the lease provides for an update.
Can my landlord raise the rent if the lease says nothing?
No. Without an express clause, the rent of a residential lease is not updated, under article 18.1 of the Spanish Urban Leases Act. If the lease provides for an update without naming the index, the Competitiveness Guarantee Index applies, not the CPI.
From when do I have to pay the updated rent?
From the month after the landlord gives you written notice of the update, stating the percentage applied. A note on the previous month's receipt is enough, and you can ask for the INE certificate. If you were never notified, the increase cannot be charged for past months.
Which CPI month should be used?
The one stated in the lease or the judgment. If it says nothing, residential leases use the latest index published on the update date. The INE publishes each month's CPI in the middle of the following month, so an update at the start of October normally uses the August CPI.
How is child or spousal maintenance updated in Spain?
As the judgment or the settlement agreement says, which almost always sets a yearly update with the CPI. The update is due even if nobody asks for it, and unpaid amounts can be claimed for the last five years under article 1966 of the Spanish Civil Code.
How much does my ex owe if maintenance was never updated?
The difference between what should have been paid each month with the updated amount and what was paid, for the last five years. With 300 euros set in January 2022 and updated every January with the December CPI, by the end of September 2026 it is 1,373.79 euros. The calculator does that sum with your figures if you choose the maintenance option.
Does it match the INE calculator?
Yes. It uses the national general CPI published by the INE and the same method, dividing the final index by the starting one and rounding the ratio to three decimals before multiplying. The data is loaded from the INE itself, so a newly published month is available straight away.