Tomás Vidal is retired and lives in Alicante. In 2023 he sold an apartment he had inherited in Benidorm and did not declare the gain because he believed that, being over 65, he was exempt. He was not: that exemption is for the main home. In September 2026 the Agencia Tributaria, the Spanish tax agency, notified him of an assessment of 12,000 €, payable by 20 October. He has his pension and a few savings, and at his bank branch he has been told that "deferring with Hacienda works out very expensive". He wants to know what it really costs.
It costs a good deal less than he has been told, provided he applies in time. What is expensive is not applying.
What the cost is made of
Deferring a tax debt has a single direct cost: late-payment interest. Article 26 of the Ley General Tributaria (the General Tax Law) defines it as an ancillary charge required for paying late, without the delay needing to be culpable. Its section 6 sets how the rate is calculated: the statutory interest rate increased by 25 %, unless the State Budget Act sets a different one.
There are three rules worth keeping in mind:
- It is calculated per instalment. Under article 53.2 of the Reglamento General de Recaudación (the General Collection Regulations), each instalment accrues interest from the day after the end of the voluntary period until its own due date, and the interest is paid together with it. The first instalment pays little interest; the last, considerably more.
- It runs even if the Agency is slow. In general, the law stops charging interest when the authorities fail to meet their deadlines for deciding. But article 26.4 expressly excludes deferral applications: if the decision is delayed, interest keeps running.
- With a bank guarantee, the rate falls. When the whole debt is guaranteed by a bank guarantee or surety insurance, article 65.4 replaces late-payment interest with the statutory interest rate, which is lower. In exchange, the bank will charge its fees.
Each year's rate is published in the Budget Act and can be checked on the Agency's website, which also offers a calculator for interest on deferrals. In this example we use an assumed rate of 4 % a year so that the figures are easy to follow; it is not the official rate.
The surcharge, which is what really makes it expensive
When a debt is neither paid nor deferred in the voluntary period, it enters the enforcement period and a second cost appears: the surcharge in article 28 of the same law. It is a percentage of the whole debt, not of the time:
- 5 % if everything is paid before the providencia de apremio, the enforcement order, arrives.
- 10 % if everything, including the surcharge, is paid within the period the enforcement order opens.
- 20 % in all other cases, and then late-payment interest is also charged.
Interest depends on time; the surcharge does not. That is why, over short periods, a single day's delay can cost more than a whole year of interest.
Tomás, with five paths over twelve months
We compare what Tomás would pay on the 12,000 € depending on what he does, assuming in every case that he finishes paying within a year.
| Path | Surcharge | Interest (assumed rate 4 %) | Total added cost |
|---|---|---|---|
| A. Pay in 12 instalments, applied for before 20 October | 0 € | About 260 € | About 260 € |
| B. As A, with a bank guarantee | 0 € | Statutory interest, lower than late-payment interest | Somewhat less than 260 €, plus the guarantee fees |
| C. Let the deadline pass and pay everything within the enforcement order's period | 1,200 € (10 %) | 0 € | 1,200 € |
| D. Let the deadline pass and pay in instalments after the enforcement order | 2,400 € (20 %) | About 300 € | About 2,700 € |
| E. Do nothing and let it be collected by seizure after a year | 2,400 € (20 %) | About 480 € | About 2,880 €, plus costs |
Path A step by step, to see where the 260 € comes from:
- Principal: 12,000 € in twelve instalments of 1,000 €, from 20 November 2026 to 20 October 2027.
- The first instalment accrues interest from 21 October to 20 November: 31 days. At 4 %, about 3.40 €.
- The last accrues interest for 365 days: 40 €.
- Adding up all twelve, the total comes to around 260 €, slightly more than 2 % of the debt.
On path D, article 53.2 of the Regulations says that the interest base does not include the surcharge, so it is calculated only on the 12,000 €. Even so, the surcharge alone multiplies the cost of path A by nine.
Applying for the deferral within the voluntary period, even on the last day, prevents the enforcement period from starting, under article 65.5 of the General Tax Law. Applying a day later already carries a surcharge. The guide on why the date matters so much explains how that day is counted.
What happens if you pay early
An instalment plan does not oblige you to wait for the last due date. If Tomás receives money halfway through, he can pay in advance through the website and interest is calculated only up to the date of payment. Article 51.3 of the Regulations applies the same logic if he pays while the application is still being processed: interest is charged up to the day of payment, not up to the proposed due date.
This turns a long instalment plan into a kind of cheap insurance: you ask for the schedule you can sustain, and pay ahead when you have cash to spare. We explain it with a case of seasonal income in how many months you can be given.
If you would like us to work out the real cost of your deferral with the current rate and your dates, you can send us the assessment or the return through the deferral form. We will tell you which path works out cheaper, without being able to guarantee that the Agency will grant the schedule as requested.
If it is refused, the interest does not disappear
A refused application does not wipe out the time that has passed. Under article 52.4.a) of the Regulations, if the application was filed in the voluntary period, the refusal opens a new payment period, and if payment is made within it, interest is charged from the end of the original voluntary period to the date of payment. There is no surcharge, but there is interest for every month the processing lasted. We deal with this in what to do after a refusal.
Comparing with a loan
The question Tomás was asking, whether it is more expensive to defer with Hacienda (as the Spanish tax office is commonly called) or to take out a bank loan, is answered by comparing two interest rates over the same periods, provided the deferral is applied for in the voluntary period. If that year's late-payment interest rate is lower than what the bank charges, fees included, deferring works out better. If it is higher, the loan may be worth it, especially if it also allows you to pay in one go and close the matter.
Where the loan usually wins clearly is when the debt is already in enforcement: paying everything within the enforcement order's period keeps the surcharge at 10 %, whereas deferring takes it to 20 %. We look at it with figures in if the enforcement order has already arrived.
The comparison between deferring, paying with a loan or providing a bank guarantee is made at Salama Tax with that year's late-payment interest rate and the real dates, not with sample percentages like the ones on this page.