Rodrigo Maestre retired in 2020 and lives in Alicante. He has a second flat in Torrevieja that he has let to a family since 2021 on a residential tenancy. As he received his state pension from a single payer and with tax withheld, he assumed he did not have to file an income tax return, and that is what he did for five years running: from 2021 to 2025, not one return. In September 2026, while arranging the sale of another property, the notary asks him about his latest returns and he discovers that the rental obliged him to file them. What he wants to know is whether he should file all five at once, one after another, or only some of them.
Filing without first doing two calculations is the most common way of paying too much.
First calculation: which years are still alive
The Administration's right to assess becomes time-barred after four years, under article 66.a) of the General Tax Act (the Ley General Tributaria), and article 67.1 sets the start of the count on the day after the end of the filing period. Taking October 2026 as the reference date, Rodrigo's table is this:
| Year | End of the filing period | Time-barred at the end of | Position in October 2026 |
|---|---|---|---|
| 2021 | 30-6-2022 | 30-6-2026 | Time-barred, unless interrupted |
| 2022 | 30-6-2023 | 30-6-2027 | Alive, with nine months left |
| 2023 | 1-7-2024 | 1-7-2028 | Alive |
| 2024 | 30-6-2025 | 30-6-2029 | Alive |
| 2025 | 30-6-2026 | 30-6-2030 | Alive, only slightly late |
The 2023 return period ended on 1 July 2024 because 30 June fell on a Sunday. One day's difference changes nothing in this case, but in surcharge calculations it can shift a month.
The year 2021 is only time-barred if nothing has interrupted the period. Article 68.1 lists as causes of interruption any action by the Administration notified to the taxpayer concerning that tax, and also any verifiable action by the taxpayer aimed at settling it. If Rodrigo received a letter in 2025 about his 2021 return, the table changes. The first thing is to check the sede electrónica, the tax agency's online office, and the mailbox.
Filing the return for a year that is still alive interrupts its limitation period: that year once again has four years ahead of it in which it can be checked. It is unavoidable and it is no reason not to file, but it is a reason to do it with all the supporting documents kept, because each year filed stays open until 2030 at least.
Second calculation: what each year costs
The amounts of tax are Rodrigo's after the rental expenses and reductions. The surcharge depends on the months of delay for each year, and the interest on the days beyond twelve months. We assume that he files everything on 15 October 2026 and a late-payment interest rate of 4 % a year, purely for the example.
| Year | Tax | Surcharge under art. 27 | With the 25 % reduction | Interest from month 13 |
|---|---|---|---|---|
| 2022 | 1,900 € | 15 %: 285 € | 213.75 € | 836 days: 174.07 € |
| 2023 | 2,050 € | 15 %: 307.50 € | 230.63 € | 470 days: 105.59 € |
| 2024 | 2,200 € | 15 %: 330 € | 247.50 € | 106 days: 25.56 € |
| 2025 | 2,300 € | 4 %: 92 € | 69 € | None |
| Total | 8,450 € | 1,014.50 € | 760.88 € | 305.22 € |
With the reduction, the total cost of putting things right comes to around 9,516 €, of which 1,066 € is surcharges and interest. If it were the tax agency that got there first, each year could carry a penalty from 50 % of the tax, and interest would run from the end of the filing period, not from month thirteen. The minimum penalty alone for the four years would add up to 4,225 € before reductions.
The year 2025 shows why it is best not to wait even one more month: with three complete months of delay the surcharge is 4 %, each further complete month will add one point, and from July 2027 it will jump to 15 % with interest.
The surcharge calculator does this calculation for each year and filing date.
The order: from the oldest to the most recent
Filing 2025 first because it is the year with the papers most to hand seems practical and usually means having to redo it. There are two reasons to start with the oldest.
The first is expenses carried forward. In 2022 Rodrigo replaced the boiler and the kitchen in the Torrevieja flat. Article 23.1 of the IRPF Act, the income tax law, limits financing interest and repair and maintenance costs to the income from the property itself in that year, and allows the excess to be deducted over the following four years. If the 2022 return is not filed first, the excess is not established and the 2023 return is calculated wrongly.
The second is the clock. The 2022 year becomes time-barred in June 2027. If there were any problem with the paperwork for that year, it is better to find out as soon as possible.
All together, with one qualification
Spacing out the filings saves nothing. The surcharge for each year depends on its own delay, so filing one a month only increases it for the years still pending. The sensible course is to prepare all of them, review them together so that the expenses and the amounts carried forward fit, and file them on the same day or on consecutive days.
The qualification is cash. If Rodrigo cannot pay the 8,450 € of tax in one go, he can defer it, but the application has to go with each self-assessment, not afterwards. And deferring without a bank guarantee makes him lose the 25 % reduction on the surcharge. We explain it with figures in paying what you owe in instalments.
If you have several years unfiled, you can send us the information through the voluntary correction form and we will prepare the table of limitation periods and costs before you file anything.
Years that show a refund
Among several pending years there is sometimes one that shows a refund. If it was not filed at the time, it is filed now like any other, late. It is not claimed by way of rectification, because there is nothing to rectify: there is no earlier return.
Filing it late does not generate a surcharge, because there is nothing to pay. If Rodrigo was obliged to file that year, it can generate the fixed fine in article 198 for filing late without financial loss to the Treasury, halved when it is done without a request. And the right to the refund also becomes time-barred after four years: a refund for 2021 could no longer be recovered.
What is checked besides the income tax return
- Whether anything has been notified. A request about any of the years turns that year into something else: there is no longer a surcharge but an assessment, and probably a penalty. The other years can still be corrected with a surcharge.
- Whether there are assets or accounts abroad. Modelo 720, the return on assets held abroad, has its own regime, separate from that of income tax.
- Whether any year's tax is approaching 120,000 €. Article 305 of the Criminal Code changes how the correction has to be made: it must be complete and paid before any notification.
- Whether the sale that brought the problem to light has its own obligations. Rodrigo's sale will be taxed in his 2026 income tax return, and it is best that it arrives with the earlier years already in order.
The order of the years, the calculation of each one's surcharge and coordinated filing are handled through Salama Tax's voluntary correction service.