Iván Soler is a graphic designer in Castelló de la Plana and has been registered as an autónomo, a self-employed worker, since 2024. In April 2025 he accepted a job as an employee at an architecture studio and stopped looking for clients of his own, although he did not deregister: he intended to take the activity up again and it seemed an unnecessary formality. He went on paying the subscription to his design software and his phone line with the business card, and in November he did a single job for a former client for 400 € plus VAT. Since the first quarter of 2025 he has not filed Modelo 303, the quarterly VAT return, again. In September 2026 he opens the sede electrónica, the tax agency's online office, for another matter and sees five quarters marked as outstanding.
The question he asks himself is the reverse of the one it seems to be: not whether anything happens for filing a nil return, but what happens for not having filed at all. Filing a 303 with a result of zero costs nothing. What costs money is the gap.
Being registered is what creates the obligation
The obligation to file the 303 does not arise from invoicing but from appearing on the tax register as a business or professional with an activity subject to VAT. As long as the census declaration says that the activity is still alive, there is a self-assessment to file every quarter, with a result to pay, to carry forward, to be refunded or zero. The system of the Agencia Tributaria, the Spanish tax agency, does not distinguish between someone who does not invoice and someone who forgets to file: it only sees a quarter that has not been filed.
When what is missing is a return that would not have meant any payment, the infringement is the one in article 198 of the General Tax Act (the Ley General Tributaria): failing to file on time without financial loss to the Treasury. The fine is fixed, 200 € per return, and its paragraph 2 halves it when you file late without a prior request. On top of that figure, the 40 % reduction in article 188.3 can also apply, which covers "any infringement" if you pay the penalty on time and do not appeal it.
Iván's five quarters, one by one
Here the first nuance appears. Not all his quarters are the same, and declaring them properly changes the result of the only one in which he invoiced.
| Quarter | Output VAT | Input VAT | Result for the period | Accumulated balance to carry forward |
|---|---|---|---|---|
| Q2 2025 | 0 € | 84 € | −84 € | 84 € |
| Q3 2025 | 0 € | 71 € | −71 € | 155 € |
| Q4 2025 | 84 € | 66 € | +18 € | 137 € after offsetting |
| Q1 2026 | 0 € | 58 € | −58 € | 195 € |
| Q2 2026 | 0 € | 63 € | −63 € | 258 € |
The fourth quarter of 2025 shows 18 € to pay if it is looked at in isolation. But if the two previous quarters are declared as what they were, quarters with input VAT and no output VAT, the balance of 155 € in his favour absorbs those 18 € and the final result is zero. With that, none of the five quarters causes any financial loss: they all fall under article 198 and none under the surcharge in article 27.
If Iván had ticked "no activity" in the first two for convenience, the fourth quarter would come out with an amount to pay, filed more than twelve months late, with a surcharge and interest. The amount is small, but it shows why the "no activity" box is not the default option.
The software subscription and the phone line were used for the activity and have invoices in his name. A personal expense paid with the same card does not become deductible because it is declared on the 303. If the activity really has stopped and there is no intention of taking it up again, the deduction of later input VAT can also be disputed.
What catching up costs, with and without a prior letter
On top of the five quarters there is the 2025 annual summary, Modelo 390, which was not filed either. If he was not exempt from it in his case, that makes six returns without financial loss. The difference between getting in first and waiting shows up in a table:
| Situation | Fine per return | Six returns | With the 40 % reduction for paying without appealing |
|---|---|---|---|
| Iván files without being asked | 100 € | 600 € | 360 € |
| He files after a request | 200 € | 1,200 € | 720 € |
There is a third row worth remembering: if the request arrives and is not answered either, article 198.3 allows the penalty for ignoring it, provided for in article 203, to be added. And the request does not usually take long, because the system detects each missing 303 without anyone having to look for it.
With figures like these, the calculation beforehand is simple and the cost is known before filing. There is no tax to argue about and no criterion to defend: only dates.
The balance in your favour does not expire straight away, but it does expire
Iván's input VAT has not been lost because it was not declared on time. Article 99.Three of the VAT Act allows the right to deduct to be exercised in the return for the period in which the tax was borne or in later ones, provided that four years have not passed since that right arose. And article 99.Five allows the excess to be carried forward to later returns for four years from the filing of the return in which it arose.
That has two practical consequences:
- The balance of 258 € can still be used if Iván starts invoicing again, because it will be deducted from whatever he has to pay.
- If he chooses to claim a refund of the balance he had at 31 December, the route is the 303 for the fourth quarter, under article 115, and whatever is claimed can no longer be carried forward afterwards.
With 137 € in his favour at the close of 2025, whether to claim the refund or keep carrying it forward depends on whether he plans to invoice soon. We explain it in carrying forward or claiming the refund.
If you are in a similar situation and want us to check which quarters are missing and how to declare them, the self-employed form gives us what we need to draw up the table before anything is filed.
When the activity is not coming back
Iván has to decide something more important than the fine: whether he is still self-employed or not. If he does not intend to take on jobs again, what ends the obligation is deregistering from the tax register with Modelo 036, which has been the only census form since Modelo 037 was abolished in February 2025. Until he files it, the online office will keep expecting a 303 every quarter.
Deregistering does not wipe out what is outstanding. The late quarters still have to be filed, as do the 303 for the quarter in which he stops and, depending on the case, the annual summary. And deregistering with the tax agency is independent of deregistering with Social Security, which is dealt with separately and has its own effects. We cover it in full in deregistering as self-employed.
If, on the other hand, he plans to start invoicing again next year, it may make sense to stay registered and file quarter by quarter, even if at zero. It is the cheapest option if the calendar is kept to, and the most expensive if it is not.
Modelo 390 and the last 303 of the year
The annual summary follows its own rule. Anyone who is not obliged to file it must complete the annual information section in the 303 for the fourth quarter, and leaving out both leaves the year unclosed. The cases are set out in when Modelo 390 is no longer needed. For Iván, the decision is made when reviewing the 303 for the fourth quarter of 2025, which is precisely the one in which he invoiced.
Three confusions that make an empty quarter more expensive
- Thinking the zero is not needed. A nil 303 is filed in two minutes and avoids a fixed fine. Not filing it is the only way a quarter with no income ends up costing money.
- Using "no activity" for everything. If there was input VAT linked to the activity, the quarter is one to carry forward, and declaring it that way can stop a later quarter from coming out with something to pay.
- Believing that stopping the activity stops the calendar. Only deregistering from the tax register stops it. Having a job as an employee changes nothing on the VAT register.
Keeping a self-employed person's quarterly calendar, including the nil periods, is part of Salama Tax's self-employed service, where we also check whether it is better to stay registered or to close the activity.