How to pay less income tax in your 2025 tax return: practical steps

IRPF
WRITTEN BY Jaume Raventós i Jané
10 Dec, 2025
How to pay less income tax in your 2025 tax return: practical steps

If you want to pay less income tax next year, you still have time. The decisions you make before 31 December can have a direct impact on your 2025 tax return.

Here are the three most effective strategies for reducing your tax bill in a completely legal and optimised way.

1. Pay off your mortgage if you are entitled to a deduction

If you purchased your primary residence before 1 January 2013, you can still benefit from the purchase deduction. The current rules are:

  • The maximum annual deductible amount is €9,040 for mortgage payments (principal + interest).
  • The deduction is 15% of this amount, i.e. up to €1,356 reduction in income tax.

In addition, the following are also included:

  • Linked life insurance
  • Compulsory home insurance for the mortgage
  • Interest rate coverage

Many people forget to include these amounts and lose out on deductions.

Check how much you have paid this year (principal + interest) and, if you do not reach the maximum, consider making an early repayment before 31 December.

2. Contributions to pension plans: up to 47% savings

Contributing to pension plans remains one of the most effective tools for reducing your income tax base.

2025 limits:

  • €1,500 in personal plans
  • An additional €8,500 in company plans
  • €10,000 in total if you only contribute to the company plan

If you are self-employed, you can contribute up to €4,250 to special pension plans for the self-employed.
Remember: the total contributions (personal + company + self-employed) cannot exceed £10,000.

3. Contribute to your spouse's pension plan

If your spouse:

  • does not earn income from work, or
  • earns less than €8,000 per year,

you can contribute up to €1,000 to their plan and deduct it in full.

This is one of the least known... and most efficient strategies.

Bonus: other ways to reduce income tax that are often overlooked

  • Donations to accredited entities (deduction of between 35% and 80% on the first €150 contributed and between 35% and 40% on the rest).
  • Compulsory union and professional association fees.
  • Contributions to political parties (20% deduction).
  • Regional deductions (rent, family, dependency, etc.).
  • Compensation for capital losses (shares, investment funds, etc.).
  • Benefits for energy-efficient home renovations (20% to 60% deduction).
  • 15% deduction for the purchase of an electric car under certain conditions (compatible with MOVES Plan subsidies).

At Grup Carles, we can help you review your individual situation, identify the options that are most favourable to you and prepare everything so that you can take full advantage of the deductions available.