kontora Calculators Pricing Guides Join the beta

Late-filing surcharge calculator

Quick answer

If you file late on your own initiative, before the tax office demands it, there is no penalty: there is a surcharge under article 27 LGT. It is a flat 1% plus 1% per full month of delay; after 12 months it becomes 15% plus late-payment interest. If you pay on time without deferral, the surcharge is reduced by 25%.

This calculator estimates what filing a Spanish tax return late costs when you move before the tax office does: the surcharge of article 27 of the Ley General Tributaria, Spain's General Tax Law. Enter the amount that was due and the complete months of delay, and you will see the estimated recargo (surcharge) plus what it shrinks to with the 25% reduction for paying on time without a deferral.

The result is an estimate, not an assessment: the real surcharge is calculated by the AEAT, the Spanish tax agency, and notified to you after you file. It also only makes sense in one scenario: you file on your own initiative, before receiving any requerimiento (formal demand). If Hacienda, the Spanish tax office, has claimed it first, we are no longer talking about a surcharge but about a penalty, and that difference is the first thing worth understanding.

The tax due on the return you are filing late.
Whole months since the deadline passed. 0 if only days.
Estimated surcharge
… €
Percentage applied
With the 25% reduction (paid on time, no deferral)

Only for filings on your own initiative, without a prior demand from the tax office (art. 27 LGT). If they demanded it first, it is a penalty, not a surcharge. Rough estimate.

Surcharge or penalty: it all depends on who moves first

Article 27 of the Ley General Tributaria draws a very clear line. If you file on your own initiative, before the AEAT sends you a requerimiento, there is no penalty and no sanctioning procedure: there is a recargo, a fixed, predictable percentage of the amount that was due.

If the requerimiento arrives before your return does, you switch regimes: the article 27 surcharge no longer applies and you move into the penalty regime, with fines proportional to the unpaid amount that can far exceed anything this calculator shows.

That is why waiting is the worst plan. As long as Hacienda has not written to you, the cost of catching up is capped and you can estimate it here; the moment they write, it no longer is.

The exact mechanics: a flat 1% plus 1% per complete month

The surcharge is calculated on the amount that was due, with two parts:

A round-number example: 4,000 euros were due and you file five months and a few days late. That is five complete months, so the surcharge is 1% plus 5%: 6%, which means 240 euros. During the first 12 months there is no penalty and no late-payment interest, only this surcharge.

From 12 complete months onwards the surcharge stops growing and settles at 15% (600 euros in the example), but from month 12 late-payment interest starts being added on top. This calculator does not include that interest: past the one-year mark, treat the result as a floor, not the total.

The 25% reduction: paying promptly is rewarded

Article 27.5 of the law cuts the surcharge by 25% if you regularise and pay without detours. In practice there are two conditions:

Back to the example: the 240 euros become 180. The calculator shows you both figures, with and without the reduction, so you can see what is at stake. If you need to defer the tax because cash is tight, that can still be the right call, but as a general rule it means losing the reduction, so run the numbers before deciding how to pay.

Nothing to pay on the return? Then there is no surcharge

The article 27 surcharge is a percentage of the amount due, so it only exists when there is tax to pay. Informative declarations, such as modelo 347 or modelo 349, and returns with no amount due follow a different path: filing them late does not generate a surcharge, but it can carry a fixed fine per return or per omitted data item.

The underlying logic is the same, though: if you come forward and file before Hacienda demands it, the fine foreseen is lower than if you wait for the requerimiento. Here too, moving first pays off.

The honest advice: file today

Each complete month that passes adds another 1%, and the counter only stops when you file, not when you decide you will. Filing today instead of next month can literally mean one percentage point less.

The practical order is simple: prepare the return with the correct figures, file it, pay or defer depending on your liquidity, and wait for the surcharge notification. The full step by step, including what to do if you cannot pay right now, is in our guide I missed a Hacienda deadline.

And so there is no next time, note the deadlines and the direct-debit cutoffs in the 2026-2027 tax calendar. kontora watches those dates for you: it warns you before every deadline and prepares the draft box by box, though filing is still done by you.

Frequently asked questions

Do days of delay count, or only complete months?
Only complete months. A few days or weeks of delay stay at the flat 1%; the extra 1% is added each time a whole month passes since the deadline. That is why the calculator asks for complete months, with 0 if none has passed yet.
What happens after 12 months of delay?
The surcharge settles at 15% and stops growing, but from month 12 late-payment interest starts to accrue. The calculator does not include that interest, so with more than a year of delay the result is a minimum, not the total cost.
How do I get the 25% reduction of the surcharge?
By paying the amount due on the return when you file it, without requesting a deferral or instalments, and then paying the surcharge within the period stated in its notification. If both conditions are met, the AEAT applies the reduction of article 27.5.
Is the calculator useful if Hacienda has already sent me a requerimiento?
No. With a prior formal demand the article 27 surcharge no longer applies: you move into the penalty regime, with fines proportional to the unpaid amount. This calculator only estimates the scenario of filing on your own initiative.
Do I pay the surcharge at the moment of filing?
No. When you file, you pay (or defer) the tax due on the return itself; the surcharge is notified by the AEAT later, in a separate document with its own payment window. The calculator's result is an estimate of that notification, not an assessment.

Rather have this calculated for you?

kontora generates your tax forms box by box, tells you how much to set aside and reminds you before every deadline.

Pricing · Calculators