Under Spain’s new system of contributions based on real income, many self-employed workers are now receiving notifications from the Social Security authorities confirming a regularisation of their contributions.
In some cases, this means an additional payment must be made. In others, a refund may be issued. While most attention is usually placed on the cash impact, there is an important aspect that is often overlooked: the effect of this regularisation on personal income tax (IRPF).
In particular, where an additional contribution is payable, this adjustment can have a positive tax consequence.
Why does this regularisation occur?
During the year, self-employed workers pay Social Security contributions based on a provisional income estimate.
Once the annual tax return has been filed, the Tax Office communicates the final net income figure to the Social Security authorities. Using this information, the correct contribution level is recalculated and compared with what was actually paid during the year.
This comparison produces the regularisation:
- either an additional amount payable, or
- a refund where excess contributions were made.
In either scenario, the regularisation has tax consequences that must be reported in the subsequent income tax declaration.
The key tax point: Social Security contributions are deductible expenses
For IRPF purposes, Social Security contributions are treated as a deductible business expense for self-employed workers in direct assessment.
This means that any additional amount paid following the regularisation reduces the taxable base in the year in which it is paid. In practical terms, although the adjustment relates to a previous year’s income, the tax effect is applied in the year of payment, not retroactively.
When an additional contribution is required, many taxpayers view it purely as a cost. However, from a tax perspective, this payment generates a deductible expense that directly lowers taxable income.
For example:
A self-employed worker was required to pay an additional 1.200€ in 2025 following the regularisation of their 2024 social security contributions.
Although this amount relates to the year 2024, as it was actually paid in 2025 it will be deductible in the 2025 income tax declaration. This deduction will reduce the taxpayer’s taxable income and, consequently, the final income tax liability for that year.
The real cost of the adjustment is therefore lower than the nominal amount paid, depending on the individual’s marginal tax rate.
No need to amend previous tax returns
It is important to note that this regularisation does not normally require filing amended tax returns for prior years.
The adjustment is reflected fiscally in the year in which the payment or refund takes place, following a practical cash-basis approach rather than a retroactive correction. This regularisation is not a sanction or an error. It is a normal consequence of the new contribution system based on real income.
Understanding its tax impact allows self-employed workers to plan ahead and avoid surprises when preparing their next income tax return. In many cases, an additional contribution will not only correct the Social Security position but will also reduce the IRPF burden.
