Thousands of taxpayers file their 2025 Spanish tax return (Renta 2025) in the very first days of the campaign to get their refund quicker — and a few hours later spot a piece of data they forgot: a regional deduction, a second employer, a fund sale. Renta Web has a built-in option that fixes the mistake with no surcharge, no penalty and no formal written request. The bad news: if the Tax Agency (AEAT) detects the error before you do, the bill changes.
Goodbye "supplementary" or "rectification request": now everything is a corrective return
You no longer need to choose between filing a supplementary return or formally requesting a rectification in writing. AEAT bundles everything into a single mechanism inside Renta Web: the corrective self-assessment ("autoliquidación rectificativa"). It works whether you underpaid or overpaid, when you want to switch from individual to joint filing, or to cancel a return you were never required to file.
When you log back into Renta Web with the same tax ID, the system detects that you've already filed and offers the option "Modify return already filed". From there you tick:
| Box | What it does |
|---|---|
| 103 | Marks the return as a corrective self-assessment of a previous one |
| 124 | Changes the filing option (individual ↔ joint) |
| 125 | Requests the return be treated as not filed (filers who weren't required) |
Renta Web automatically pulls in the receipt numbers and the amounts already paid or refunded: as a rule, you won't need to type any figures by hand.
Who's affected
- Anyone who filed before reviewing their tax data and later spotted a missing employer, a regional deduction or a capital income item.
- Couples who picked individual filing when joint suited them better (or vice versa): you can change the option until 30 June.
- People who received back-pay from work after filing (article 14.2.b of the Spanish IRPF Act): the corrective return must record the date of receipt.
- Beneficiaries of mortgage floor-clause refunds who forgot to include them (Additional Provision 45 of the IRPF Act).
- Anyone who filed without being required to and prefers to have the return treated as not filed, so they aren't tied to its content.
How to do it in Renta Web, step by step
- Log into Renta Web with Cl@ve, a digital certificate or your reference number.
- On the start screen choose "Modify return already filed".
- Inside the file open "Return sections" → "Modify Renta 2025 return already filed".
- Tick box 103 (corrective return), or box 124 if you only want to switch individual ↔ joint.
- Correct the data in the affected sections: the previously paid amounts appear automatically.
- If the reason matches one of the specific cases (back-pay, floor-clauses, reinvestment, pension plans, dismissal, change of residence…), select the corresponding letter; otherwise pick "ñ) Other cases".
- Click "File return" and choose the payment method or refund account.
Mind the amounts already paid or refunded
If the corrective return shows more tax to pay, the original payment terms and dates are kept; only the new amount is paid separately. If it shows a higher refund or flips from "to pay" to "to refund", any pending direct debits are cancelled and AEAT calculates the excess to reimburse you.
The tip that avoids the penalty
Correct it before 30 June
While you're still inside the voluntary filing period (until 30 June 2026), the corrective return triggers no surcharges and no penalties, even if you end up paying more. After that date, a late return without prior notice activates the surcharge in Article 27 of the General Tax Act: 1 % plus another 1 % for each complete month of delay during the first year (capped at 12 %), and 15 % + late-payment interest from month 12 onwards. And if AEAT issues a notice before you correct, the penalty in Article 191 of the General Tax Act kicks in: from 50 % (minor) to 150 % (very serious).
What if you filed without being required to?
Box 125 is the least known piece. It covers two cases:
- You weren't required to file and you'd rather cancel what you submitted: tick the first option in the request window.
- You don't qualify as an IRPF taxpayer (residents in foral territory or non-residents in Spain who filed Form 100 by mistake): tick the second one as well.
If the original return already had a refund agreed, AEAT will require you to repay it. Box 125 will appear ticked on the filing receipt alongside box 103.
Context
According to the official Tax Agency guide on modifying a Renta 2025 return already filed, the corrective self-assessment is the single procedure to fix errors or omissions in returns already filed and to change the filing option. AEAT reminds taxpayers that the joint or individual option becomes irrevocable once the filing deadline ends, unless it's changed before that closure through box 124. For other changes after the deadline the ordinary regime for late returns applies, including the surcharges set in the General Tax Act where appropriate.
Going deeper
- Review the Renta 2025 campaign so you don't miss the key dates.
- If you're still unsure between individual and joint filing, see the guide on when each option pays off.