The 2025 personal income tax declaration campaign is about to get underway, with millions of taxpayers pending the key dates that mark when and how they must comply with their tax obligations. From April 8online presentation will be available, followed by telephone on May 6 (upon request from April 29) and in-person attention in offices from June 1, by appointment from May 29. He June 30 It will be the last day to complete the procedure by any of the planned means.
But, in addition to the declaration for the 2025 financial year, many citizens are unaware that it is possible to correct or modify past self-assessments, which can be both an opportunity to recover the money and a way to avoid sanctions if errors are corrected before the Tax Agency detects them.
Thus, Spanish legislation allows you to modify income tax returns for up to the last four years. For example, during 2026 the declarations corresponding to 2024, 2023 and 2022 can be reviewed. If they have elapsed more than four years From the end of the official submission period, the option to complain or correct disappears, except in very exceptional situations. As explained from TaxDownthe taxpayer can benefit if he finds forgotten deductions, such as maternity that allows him to recover up to 1,200 euros for each year not declared, or if it corrects errors that improve the result.
Consequences and advantages of regularizing the tax situation
The voluntary correction of the declaration has different consequences depending on the case. If it is the taxpayer himself who detect and correct the error before After the Treasury initiates a procedure, only surcharges or late payment interest will be applied, but not fines. On the other hand, if the Tax Agency discovers the omission or failure, economic sanctions will be added to the regularization.
Inside the four-year termyou can claim the refund of amounts deposited in excess or apply deductions not requested at the time. If the taxpayer forgot to submit the declaration, the situation can also be regularized, although the corresponding surcharges will have to be assumed depending on the time elapsed and if the Administration has already initiated any requirements.
The Income Tax return campaign for the 2025 financial year starts on April 8.
How to modify the income tax return from previous years
The procedure to claim or modify an old declaration is accessible and can be carried out entirely online. The first step is to enter the electronic headquarters of the Tax Agency and access the specific section of the year you wish to review, using the digital certificate, the electronic DNI, Cl@ve PIN or the reference number.
Within the RentaWeb platform, the user must locate the “Processing Status” section and select “Modify declaration”. Two main options are presented here: the self-assessment rectification and the complementary declaration. The rectification (box 127) It is designed for those who seek to have the Tax Agency return money or recognize deductions not applied at the time. For example, if a taxpayer discovers that in 2020 they were entitled to a deduction and did not request it, they can initiate this process to recover the outstanding amount.
The supplementary declaration (box 107)for its part, is used to declare income or omissions that imply a result in favor of the Treasury. That is, if you forgot to declare income or any information that would mean paying more, this is the appropriate procedure. Once the corresponding option has been selected and the modification has been made, it is enough to validate and submit the new declaration. The Tax Agency will review the documentation and, if satisfied, will proceed with the refund or require additional payment as appropriate.
After completing the process, the Treasury may request additional information to verify the veracity of modified data. Therefore, it is essential to retain all documentation that justifies the changes made. Monitoring of the file can be done from the electronic headquarters itself, where information will be provided on the resolution and the possible steps to follow. If the declaration was originally submitted on paper, it will be necessary to digitize the relevant documents to attach them during the online process.
Recommendations for the taxpayer
Many people doubt whether they will receive a penalty for voluntarily correcting their return. The answer is clear: if the correction is made before any requirement, only surcharges or interest will be applied, but not fines. For example, if you forgot to apply a deduction for the birth of a child, it is still possible to claim a refund of the corresponding amount, as long as no more than four years have passed.
The most recommended is act quickly when an error or omission is detected. Periodically reviewing old returns can mean significant savings and avoid future problems with the Tax Agency. The current regulations favor those who regularize their situation voluntarily, allowing them to recover unapplied deductions and avoid serious penalties.
