Child maintenance and inflation
Child maintenance in Spain and the yearly CPI update: how to calculate it, with an example
Published on · Updated on · 6 min read
This guide is about Spain: it describes the pensión de alimentos (child maintenance) in Spanish law and uses the Spanish CPI, called IPC (Índice de Precios de Consumo). If your order comes from another country, none of this applies.
Many Spanish divorce agreements say that child maintenance ‘is updated every year according to the IPC’. The sentence is short; the sum isn’t: which index, which month, from when, on which figure. Here is the formula, an example with the figure published by the INE, and the mistakes that come up most.
First: what your agreement says
The Civil Code asks the convenio regulador (the agreement the judge approves in a divorce) to include each parent’s contribution to child maintenance and its update bases (art. 90.1.d). That’s where, or in your court order, the following is set:
- Which index: usually the national general CPI of the INE.
- Which month: the annual change of a particular month (for example, the one ending in December, or the month before the update).
- From when it applies: often from January, but it can be another date.
- What happens if the CPI is negative.
If your agreement has no update clause, child maintenance doesn’t rise by itself. And what each parent pays or receives is set by your agreement or court order, not by this guide.
The formula
With the annual CPI change (the percentage the INE publishes):
New amount = current amount × (1 + CPI rate / 100)
With the indices directly, which is what the INE calculator uses when you compare the same month in two years:
New amount = current amount × index of the final month / index of the starting month
Both give the same result apart from rounding.
Example with the INE figure
On 14 October 2026 the INE published the final September figure: the annual general CPI rate was 4.9%, six tenths more than in August (4.3%).
Just as an example, with child maintenance of €300 updated with that figure:
| Step | Calculation | Result |
|---|---|---|
| Annual CPI rate | 4.9% | 1.049 |
| New amount | 300 × 1.049 | €314.70 |
| Increase | 314.70 − 300 | €14.70 |
Note: this uses one specific month. The month that counts is set by your agreement. If it says, for example, “the change over the twelve months before December”, the figure will be December 2026’s, which hasn’t been published yet, and it will be different.
If more than a year goes by
You don’t add percentages: you chain them. A made-up example: €300 rises 4.9% to €314.70. The next year the CPI is 3.0% (invented for the example): 314.70 × 1.03 = €324.14. Adding 4.9 + 3.0 = 7.9% would give €323.70: 44 cents less every month.
The safest way is to use the indices of the starting and final months, which already include everything that happened in between.
Where to check it
The INE publishes the CPI every month, with the general index and the annual change, at ine.es (in Spanish). It also has an official calculator, El IPC en un clic, to update an amount with the general CPI: you pick the month, the start and end year, type the amount, and it gives you the increase and the result. It’s meant for full-year periods, that is, the same month in one year and the next.
To see how recent the last figure is, check the INE press section: September’s came out on 14 October, in the middle of the following month.
Common mistakes
- Using the monthly change instead of the annual one. The monthly figure is one month’s rise. To update yearly child maintenance you use the annual figure (or the two end indices).
- Looking at the wrong month. September gives 4.9%, but your agreement may ask for another month.
- Using your region’s CPI instead of the national general one. Unless the agreement says so, use the general one.
- Adding percentages across years instead of chaining them.
- Starting from the original figure and not the last updated one.
- Letting an update pass without talking about it. Before changing the amount or claiming differences, talk and write it down. What you can claim for past periods depends on your case; speak to a lawyer.
When it’s paid and how much
Child maintenance is paid monthly in advance (Civil Code art. 148). If the update applies in January, the new figure is for the instalment that starts then. If your agreement sets another date, that one applies.
If the agreement isn’t clear
If it isn’t clear which CPI or which month, the best option is to agree it in writing. If circumstances have changed substantially, the measures can be changed through the courts or with a new agreement (art. 90.3). For that, speak to a lawyer or a family mediation service.
Keeping track with Vaivén
In Vaivén you set up the child maintenance and its update date, note the CPI that applies (with a link to the INE calculator), and the app works out the new amount. It keeps the history: each amount with the date it applies from, and which months are paid. Child maintenance with CPI is part of Full Vaivén (€9.99, once). If you don’t buy, nothing’s deleted and the calendar stays free.
In Vaivén
The child maintenance tool works out this year's amount with the Spanish CPI and shows which months are paid. Part of Full Vaivén. See: Money
Frequently asked questions
Does child maintenance in Spain update itself with the CPI?
Only if your agreement or court order says so. The Civil Code asks the divorce agreement to include child maintenance and its update bases (art. 90.1). If there's no update clause, the amount doesn't rise by itself.
Which CPI is used to update child maintenance?
The one your agreement sets. Usually it's the national general CPI published by the INE, applied once a year using the annual change of a specific month. Unless it says otherwise, your region's own CPI isn't used.
Where do I check the CPI?
On the INE website (ine.es, in Spanish). Its 'El IPC en un clic' calculator updates an amount between two full years and gives you the increase and the new amount.
What if the CPI is negative?
It depends on your agreement: some say child maintenance doesn't go down, others say it does. Read it before applying anything.
Can I add up the percentages of several years?
No. Each increase applies to the already updated amount, so they chain by multiplication. Using the indices of the two end months avoids mistakes.
Sources
Sources checked in October 2026.
- INE (Spain's statistics office). Consumer Price Index (IPC), September 2026, press release (in Spanish) (final figure published on 14 October 2026: annual general rate 4.9% (4.3% in August))
- INE. El IPC en un clic: updating an amount with the general CPI (in Spanish) (official calculator, for full-year periods (the same month in two different years))
- BOE. Código Civil (consolidated text, in Spanish), arts. 90, 93, 146 and 148 (the divorce agreement and update bases, each parent's contribution, proportionality, payment in advance by month)