Marta is a supply teacher in Seville. In 2025 she earned €17,400 from the Andalusian Consejería de Educación (the regional education department) and, after a posting of a few months in Extremadura, €6,100 from the Extremadura regional administration, and she let out an inherited flat for €7,200 a year. In June 2026 she was sitting on a panel for the public teaching examinations and her income tax return slipped her mind. On 15 September she opened Renta Web, the tax agency's online return program: it showed €1,300 to pay. She wanted to know whether she would be fined, how much each extra week was costing her and whether she could still file a joint return with her husband, which suited him.
The first thing we told her is what anyone in her situation should know: as long as the tax office has not written to you, filing your income tax return late costs a recargo (a surcharge for filing late unprompted), not a penalty, and the surcharge grows month by month. The second she liked less: the option of a joint return can no longer be chosen freely. The IRPF obligations for the self-employed and everyone else are summarised on our self-employed in Spain page.
The price of delay, month by month
The return for IRPF, the personal income tax, Modelo 100, is filed during the income tax campaign, from April to 30 June of the following year. If it is filed after that without a prior request from the tax office, article 27 of Ley 58/2003, the General Tax Act (Ley General Tributaria), applies a surcharge that starts at 1 % and adds one point for each full month of delay. After twelve months, the surcharge is 15 % and late-payment interest is paid on top. If everything is paid at once, the surcharge is cut by 25 %.
| Filing date | Full months of delay | Surcharge | On €1,300 | With the 25 % reduction |
|---|---|---|---|---|
| Up to 30 July | 0 | 1 % | €13 | €9.75 |
| 15 September | 2 | 3 % | €39 | €29.25 |
| 15 December | 5 | 6 % | €78 | €58.50 |
| July of the following year | 12 or more | 15 % + interest | €195 + interest | €146.25 + interest |
For Marta, filing on 15 September and paying at once, the oversight costs €29.25. If she waits for the Agencia Tributaria, the Spanish tax agency, to send her a formal request, the surcharge disappears and a penalty of at least 50 % of the tax appears instead: €650 before reductions. You can work out your own figure with the late-filing surcharge calculator.
Why she had tax to pay: the two payers
Marta did not think she had to file: she had "only" earned €23,500 from employment. But the IRPF Act (article 96) lowers the threshold from €22,000 to €15,876 when there is more than one payer and the second and subsequent payers together pay more than €1,500. Her second payer, the Extremadura administration, paid her €6,100, so she was obliged to file. And she also had the rental income, which on its own creates the obligation. Each payer's withholdings were calculated as if it were the only one, and that is where the tax to pay came from. When you are obliged to file is explained in how to tell whether you have to file an income tax return.
What you lose by filing late (besides the surcharge)
The option of joint taxation
Article 83.2 of the IRPF Act says that the choice between individual and joint taxation cannot be changed once the filing period is over. It adds that, if no return is filed, the taxpayers are taxed individually, unless they state their choice within ten days of a request from the tax authorities. If neither spouse has filed, there is room to argue the point; if he has already filed an individual return on time, the joint option is closed.
Payment in two instalments without interest
Within the deadline, the tax can be split into 60 % in June and 40 % in November at no cost. Outside the deadline, that option disappears: either you pay everything, or you apply for an ordinary deferral with late-payment interest.
Direct debit
Nor can a return filed late be paid by direct debit. It is paid with an NRC (the payment reference code your bank gives you), by debit to your account from the online office or by card.
If you are due a refund
If the return you forgot to file shows a refund, there is no surcharge, because there is nothing to pay in. What the law provides for is an offence for failing to file on time a self-assessment that causes no financial loss (article 198 of the General Tax Act), with a fixed fine that is halved when it is filed late on your own initiative. Whether it is imposed in each case we cannot guarantee. What is certain is that the right to the refund lasts for four years and that the six months the Agencia Tributaria has to make the refund start to run from when you file.
If you would like us to review your late return before filing it, tell us about it in the self-employed form, which also deals with employees and pensioners whose return is outstanding.
Renta Web details that complicate a late return
A late return is filed with that year's program, not the current year's. Renta Web keeps earlier years open, and you have to choose the right one: a 2025 return prepared under the 2026 rules comes out wrong.
A formal request is not always a letter: a notification in your official electronic mailbox (known in Spanish as the DEH) that you have not opened also counts, and after ten days it is treated as notified. If you have electronic notification switched on, check the inbox before filing. We explain it in counting deadlines and electronic notification.
And if the oversight affects several years, they are filed one by one, starting from the oldest year not yet time-barred, each with its own surcharge according to its own delay.
New arrivals: the first year nobody warns you about
A large share of the forgotten returns we see belong to people who moved to Spain and did not know that the first year already required a return. If in the year you arrived you spent more than 183 days here, you are resident for the whole year and declare your worldwide income for that full year, including what you earned before moving, with the mechanisms in the tax treaty to avoid double taxation. Anyone who opted into the special regime in article 93, the so-called Beckham regime, does not file Modelo 100 but Modelo 151, and forgetting it has its own rules. And if you are self-employed, the quarterly Modelo 130 payments you made during the year are deducted in the late return exactly as in one filed on time: the surcharge is calculated on what is left to pay after deducting them, not on the total tax.
Each year is a separate return. The 2025 rent goes in the 2025 return, even if you file it in 2026 or 2027. Putting it in the following year's return regularises nothing: it leaves one year undeclared and over-declares the other, and the Agencia Tributaria will see it that way when it cross-checks the rental data.
Today's checklist
- Go into Renta Web for the right year and download your tax data.
- Check that all your payers are there and, if you own property, the rents and the IBI bills (the annual municipal property tax).
- Check whether your spouse has already filed, and how, before choosing individual or joint.
- File and pay at the same time, to secure the 25 % reduction of the surcharge.
- If you cannot pay it all, file anyway and apply for deferral in the return itself.
Marta filed that same 15 September, individually, and paid by card. Twenty-nine euros more than she would have paid in June. It is not always that cheap, but it is almost always cheaper than waiting.