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Checklist: What documents do you need to fill in a Belgian income tax return?

00:44 01/06/2024

Hopefully, you have put all the documents you received in one envelope or box: your salary or pension statement for 2023, certificates of donations to charities etc.

So, which documents and certificates do you need to prepare your income tax return?


  • salary statement;
  • holiday pay statement (if not paid by your employer);
  • unemployment benefit statement;
  • illness or occupational injury benefit statement;
  • pension statement;
  • all documents evidencing tax deductible expenses relating to your job;
  • for self-employed: certificates confirming social security paid, private pension (VAPZ/PLCI) contributions, reimbursement of professional loans;
  • your personal contribution to the mutuelle/ziekenfonds;
  • if you have real property, the annual bill(s) for the property tax (précompte immobilier/onroerende voorheffing);
  • if you have an overseas property, the letter of the tax authorities determining the cadastral revenue;
  • if your tenant is a company or a professional: a summary of the rent received and the identity of the tenant(s);
  • if you have taken out a new mortgage: the certificate delivered by the bank with details of the mortgage;
  • mortgage payment certificate(s);
  • mortgage insurance premium certificate;

If you have income from savings and investments:

  • bank statements showing interest and dividends received;

Certificates justifying deductible expenses:

  • premium(s) paid for ordinary life insurance by way of long-term saving;
  • contributions paid for pension saving;
  • titres-service /dienstencheques;
  • payments for childcare;
  • premiums for legal expenses insurance ;
  • personal contribution to public transport season ticket;
  • tax-deductible gifts;

Other documents:

  • proof of maintenance paid (+ identity of the beneficiary);
  • summary of maintenance received (+ identity of the payer);
  • certificates relating to energy saving expenses and expenses (with invoices and proof of payment);
  • certificate of co-parenting arrangement;
  • advance tax payments;
  • self-employed : income, social security paid in 2021 and list of expenses.

Other useful information:

  • changes in the family situation (marriage, divorce…);
  • name and date of birth of dependent children;
  • identity of other dependents;

It is also a good idea to start with last year’s tax bill to see which codes you used then.

What to check in a pre-completed tax return or tax proposal

  • Are all children (assuming they are in joint custody of both parents) or other dependants listed correctly?
  • Childcare costs for children between 3 and 14 should have been entered. But this is only possible if the childcare provider has informed the tax authorities in due time. Therefore, carefully compare the pre-filled data with the certificates you received. Also keep in mind that for toddlers under three, the information is not pre-filled.
  • If you married in 2023 (and you were not legally cohabiting in 2022) and your partner has limited income, you are entitled to a tax break.
  • Those who live more than 75 or 125 km from work can benefit from an increased deduction for the commute. This increase applies even if you have been working from home.
  • Check that other expenses for which you can get a tax break are also included andfor the correct amount. Consider donations to charities, titres service, pension and long-term savings or a charging station.
  • Did you pay or receive maintenance fees? The tax authorities do not have this information, that will normally be missing from the Tax Proposal.
  • Mortgage loans and/or life insurance are usually included, but it is wise to check. If you have taken out a new loan to acquire a property in Wallonia in 2023 or if you have multiple life insurance policies, you will undoubtedly need to amend your proposal.
  • Do you own property other than your main residence, such as a second residence or a buy-to-let? Especially if you bought or sold something in 2022 or 2023, or changed the usufruct, if you moved in 2023 or if in 2022 your marital status changed (marriage, divorce...), you should check the Tax Proposal carefully. If you take a tenant who to someone who uses the property professionally, you will very likely need to amend your proposal. If you were an owner for only part of the year in 2023, report the non-indexed cadastral income in relation to the period (on a daily basis) during which you were an owner.
  • Up to €800 in dividends is exempt from withholding tax, but this exemption is never automatically applied.
  • If in 2023, you or your partner or children had a bank account or life insurance policy outside Belgium, that is not something that the tax authorities will know. Even if you no longer have this account or life insurance in 2024, you must file a tax return.
  • If you, your spouse or legal cohabitant, or minor children were founders or beneficiaries of a legal arrangement in 2023, you must not only file a tax return, but also compulsorily attach an attachment.

More from our 2024 income tax guide

  1. When do I need to file my Belgian income tax return?
  2. Belgian income tax returns for families
  3. Online or on paper?
  4. Filing online
  5. Understanding the paper tax return
  6. Checklist: What documents do you need?
  7. The return in detail
  8. Belgian income tax: There's nowhere to hide
  9. A guide to cross-border taxation
  10. Help! Where to get assistance with your tax return
  11. Understanding your Belgian income tax bill
  12. How do I appeal?
  • This guide was written by Marc Quaghebeur, an international tax lawyer at Cabinet DAVID. It is a general introduction based on current understanding of the law. It is not to be taken as a suitable alternative for individual advice. If you have a question, you can contact him by clicking on his name.
Written by Marc Quaghebeur