Got box 110 of the Spanish VAT return wrong? How to fix it since 2024 (no more complementaria or rectificación)

You filed this quarter’s modelo 303, and two weeks later you realise box 110 –the VAT-to-offset balance you were carrying forward– wasn’t the right one. You put in too much, too little, or forgot it entirely. You search for how to fix it and find articles talking about filing a “complementaria” or asking for a “rectificación”, and you’re not sure which one applies to you.

The short answer is: if your quarter is Q3 2024 or later, neither. Since then there’s a single mechanism, the autoliquidación rectificativa (rectifying self-assessment), which replaces both for VAT.¹ Let’s walk through it with the specific case of box 110, where this mistake is costliest because it carries a balance from one quarter to the next.

Before 2024 you had to pick the right route; now you don’t

Through Q3 2024, if you made a mistake on a modelo 303, you first had to decide which route to correct it through, and picking the wrong one was part of the problem: if the error had made you underpay, you filed a complementary self-assessment (autoliquidación complementaria); if it had made you overpay or claim less than you were owed, you had to open a rectification request (solicitud de rectificación), a separate procedure that didn’t take effect on filing but waited for an administrative decision.

Since the Q3 2024 modelo 303 (or September 2024 if you file monthly), that distinction disappears for VAT. It doesn’t matter whether the mistake benefits you or costs you: the route is the same, a rectifying self-assessment, and it takes effect on its own, without waiting for the Tax Agency to resolve anything.² If your mistake belongs to an earlier quarter, the traditional complementaria or rectificación still applies.

How to file it

On the modelo 303 itself you tick the “Autoliquidación rectificativa” box, and two more things are mandatory alongside it: the receipt number of the return you’re correcting, and at least one reason for the correction.³ A box-110 carry-forward mistake –an amount that doesn’t match the pending balance from the previous quarter– falls under the general reason (“corrections, except administrative-criteria disagreement”), not the special reason reserved for disputing the Tax Agency’s interpretation of a rule.

From there, which boxes you fill in depends on which way the result moves:

• If the correction raises what you owe (you entered more box-110 balance than you actually had, so you offset too much and paid too little): box 70 picks up the amount already paid on the previous return, and you pay the difference.
• If the correction lowers what you owe, or triggers a refund (you entered less balance than you should have, so you offset too little and overpaid): depending on whether you’d already paid, already been refunded, or the refund was still pending, the amount goes into box 70, box 109, or the earlier refund procedure is simply closed out.³

A worked example with box 110

Picking up the example from the article on VAT to offset from previous quarters: Q1 came out at −€400, and in Q2 that €400 had to go into box 110.

Imagine that, filling in Q2, you entered €300 instead of €400 –a simple slip copying the figure across–. Q2’s result, which was €600 of output VAT minus input VAT, ended up at €600 − €300 = €300 to pay, when correctly offsetting it should have been €600 − €400 = €200. You overpaid by €100, and on top of that €100 of Q1’s balance is left uncompensated that shouldn’t have been.

To fix it: you file a rectifying self-assessment for Q2 (not Q3, and you don’t “adjust” the next quarter’s box 110 to even it out some other way, because the mistake sits in that specific return). In it, box 110 becomes €400, the result drops to €200, and since you’d already paid €300, the €100 difference gets refunded to you.

If you fix it after the deadline

A rectifying self-assessment can be filed at any point before the Tax Agency’s right to assess, or your own right to claim a refund, has lapsed –in practice, four years– but if you file it after that quarter’s filing deadline, it’s treated as late (extemporánea).³

That matters above all when the correction makes you pay more than you paid at the time (the first case above, in reverse): in that scenario the rules for complementary self-assessments under article 122.2 of the General Tax Law apply, which brings in the surcharge for late filing under article 27 of that same law –1% plus another 1% per full month of delay during the first year, and 15% from the one-year mark, with no late-payment interest before that point.⁴ If instead the correction generates a refund or lowers what you owed, there’s no surcharge: someone who corrects a mistake that was against their own interest isn’t penalised for fixing it.

When you still need the traditional rectification request

The rectifying self-assessment doesn’t cover everything. The traditional procedure (articles 126 to 128 of the tax management and inspection regulation) is still required for:

1. Correcting VAT you wrongly charged a client. If the mistake isn’t yours towards the Tax Agency but towards a third party you invoiced with the wrong VAT, that has its own procedure.³
2. Transactions under special regimes in Chapter XI of Title IX of the VAT Act (the equivalence surcharge, the travel agency regime, and similar).
3. When the underlying reason is that the rule applied breaches a higher-ranking rule (an Act, the Constitution, EU law): here you can choose between the rectifying self-assessment or the traditional request, and only the latter lets you attach supporting documentation.³

A copy-paste mistake on box 110’s balance falls into none of these three cases: it’s the general scenario, and it’s fixed with the rectifying self-assessment, no further detours.

How does Cuéntamo help with this?

The box 110 mistake almost always comes from the same thing: a number copied by hand from one return to the next, three months later, with nothing to flag it if it doesn’t match. In Cuéntamo, the balance to offset carries forward on its own from one quarter to the next, so there’s no figure to copy and, therefore, no copying mistake to fix. If you still find that an old quarter –say, from before you started using the app– was filed wrong, you now have the exact mechanics to correct it without having to guess whether you need a complementaria or a rectificación.

To see where each box in the quarter comes from, the article on how to calculate quarterly VAT walks through it step by step, and the one covering the full modelo 303 shows where each field fits.

FAQ

Does the VAT complementaria still exist?

Not for modelo 303, not since Q3 2024 (or September 2024 if you file monthly): it was replaced by the rectifying self-assessment, a single route that works whether the mistake makes you pay more, pay less, or claim a refund.

Which box do I tick to correct a modelo 303?

The “Autoliquidación rectificativa” box on the form itself, along with the receipt number of the return you’re correcting and at least one reason for the correction.

Do I need to wait for the Tax Agency to approve the correction?

No. Unlike the old rectification request, the rectifying self-assessment takes effect on filing, without waiting for a prior administrative decision.

Will I be charged a surcharge for fixing a box-110 mistake?

Only if the correction means you now owe more than you paid at the time and you file it after the deadline: then the late-filing surcharge applies (1% plus 1% per full month, up to 15% after a year). If the correction refunds you money or lowers what you owed, there’s no surcharge.

Does the rectifying self-assessment cover any modelo 303 mistake?

Almost all of them, but not VAT you wrongly charged a client, transactions under special regimes (equivalence surcharge, travel agencies…), or cases where the reason is that the rule applied breaches a higher-ranking one: those still follow the traditional rectification-request procedure.

References

Figures as of 2026. The VAT rectifying self-assessment has been in force since Orden HAC/819/2024, applicable to returns from September 2024 (monthly) or Q3 2024 (quarterly) onward; earlier quarters are still corrected via the traditional complementaria or rectification request.

This article is checked against official sources and reviewed periodically. If you spot something out of date, write to us at [email protected].