Marina teaches yoga in Granada, in premises rented by the hour and in people's homes. Her students are private individuals, so nobody withholds tax from her and she files Modelo 130, the quarterly payment on account of income tax, every quarter. In 2026 she had a first half-year of unexpected expenses (an injury, two months with fewer classes) and decided to file the 130s for the first and second quarters acknowledging the debt but without paying them: €620 and €720. She planned to catch up «when the income tax refund comes in». What she did not know is that the refund already had another destination.
From voluntary to enforcement stage, in Marina's case
Each unpaid 130 is a separate debt. The first quarter's fell due on 20 April 2026 and the second's on 20 July. The day after each due date, with neither payment nor a deferral request, that debt entered the periodo ejecutivo, the enforcement stage. From then on the surcharges in article 28 of the Ley General Tributaria, Spain's General Tax Act, apply according to when payment is made:
| When payment is made | Surcharge | Q1 (€620) | Q2 (€720) | Total |
|---|---|---|---|---|
| Before the providencia de apremio (formal demand for payment) is served | 5 % | €651 | €756 | €1,407 |
| Within the period the demand grants | 10 % | €682 | €792 | €1,474 |
| After that period | 20 % + interest | €744 + int. | €864 + int. | €1,608 + interest |
The calculation is straightforward: 620 × 1.05 = 651; 620 × 1.10 = 682; 620 × 1.20 = 744. And the same with 720. The difference between the first row and the last is €201 plus interest, on a debt of €1,340: an extra 15 % for not having acted in time.
The income tax refund that will never arrive
Marina's renta, the annual income tax return, for 2026 will be filed in spring 2027. Suppose that, with her expenses and her injury, it shows a refund of €900. What almost nobody tells you is that the Agencia Tributaria, the Spanish tax agency, does not pay a refund to someone who owes it money in the enforcement stage: it offsets it automatically against the outstanding debt. If by then Marina still has not paid and both debts are already at the 20 % stage:
- Outstanding debt: €1,608 plus the interest accrued.
- Recognised income tax refund: €900.
- Automatic offset: the refund is applied to the debt and Marina receives nothing.
- Debt still alive: €708 plus interest, which continues its course in the enforcement stage.
Marina would find out when the refund failed to arrive and she checked her position on the tax agency's online office. The offset is not bad in itself (the debt is paid with money that was hers), but it comes late, with the maximum surcharge already applied and without her choosing the moment. And it is worth not mixing things up: the renta settles the tax for the year, but it does not wipe out the debt from the unpaid 130, which has a life of its own.
If the debt keeps growing: seizures
Once the period in the demand for payment has passed, the tax authorities can seize assets without going to court, following a legal order that starts with money. In practice, the first thing you see is a hold on your bank account: the bank receives the seizure order and freezes the balance up to the amount of the debt. If Marina also had a salary, it too could be seized, but within the limits of the Ley de Enjuiciamiento Civil, the Civil Procedure Act, which protect an amount equivalent to the minimum wage and set rising percentages above it. Movable and immovable property come later and are rare with debts of this size.
Before it gets that far, a debt in the enforcement stage also has indirect costs: it prevents you from obtaining the certificate of being up to date with your taxes, which some grants and aid schemes for the self-employed require.
Counting on the income tax refund to catch up means counting on money the tax office has already earmarked for your debt. If you cannot pay a 130 on time, what works is requesting instalments within the same filing period: for €620 or €720, with no guarantee and a few euros of interest. That request keeps you out of the enforcement stage and, with it, out of every surcharge in the table. And if you are already in the enforcement stage, paying before the demand arrives keeps the surcharge at 5 %.
Finding out in time: how notices reach you
A good share of the 20 % surcharges we see are not because the taxpayer decided not to pay, but because they never learned of the demand for payment. Individuals who are not obliged to deal with the tax authorities electronically receive notices on paper, at their tax address. After two failed attempts, the notice is published in the Boletín Oficial del Estado, the official state gazette, and is deemed served if you do not come forward. Someone who has moved without updating their tax address, or spends periods away, can lose the 5 % and 10 % windows that way without knowing it.
To avoid this, the simplest thing is to check the online office regularly (the debts section and the notices section) and keep your tax address up to date with Modelo 036. Anyone who has signed up voluntarily for electronic notices has the opposite problem: a notice is deemed served ten days after it becomes available even if it is never opened, so the mailbox has to be checked regularly. The guide on counting deadlines and electronic notices explains how those days are counted.
If you close down with 130s still owed
Deregistering as self-employed does not extinguish the debts from the earlier period. Unpaid 130s carry on through the enforcement stage even if you no longer invoice, and offsetting against future refunds, or seizing a salary if you move into employment, remain possible. Closing the activity is a good moment to clear what is outstanding, because the last 130 and the last renta as a self-employed person usually give a complete picture of what is owed.
Nor is limitation a way out. The period to collect a debt is four years, but every notice, every seizure order and every offset interrupts it and resets it to zero. A debt from an unpaid 130 only lapses if the tax authorities do nothing for four years in a row, and with today's automatic cross-checks that is very rare.
What Marina can do today
In September 2026, the first thing is to check on the online office which stage each debt is at. If no demand has been served, paying now costs €1,407. If she cannot pay it all, she can request a deferral in the enforcement stage too: the surcharge already accrued does not go away, but the escalation stops and seizures are avoided. And for the third quarter, due on 20 October, it is best to file it with its payment or with its instalment request, not with a simple acknowledgement of the debt.
If you would like us to review the state of your debts and the calendar for the coming quarters with you, the self-employed form is there for that. The guide to Modelo 130 explains the calculation, and the one on deferring within the voluntary period the procedure that would have avoided everything above.