Personal taxation · Luxembourg
Form 100 or 163? Luxembourg tax return checker
This diagnostic points you to the procedure to examine based on a few answers. It does not check every case of mandatory assessment, does not calculate tax and never concludes that there is no obligation when the data is insufficient.
Financial Services Luxembourg · Licensed accountant · Head of the firm: Mickaël LOC. Editorial update: .
Your orientation for 2025 income
No account or documents needed. Your answers stay in this browser while you use the page.
What the tool checks
The questionnaire distinguishes an express request for Form 100, an already verified admission to assessment by way of tax return, and a need to regularise salaries or pensions. It also identifies the options and income that require further examination.
A result of "annual tax adjustment (Form 163) to examine" does not confirm eligibility. The conditions specific to residents or non-residents, and the expenses claimed, still need to be checked.
What the tool does not decide
- Disputed tax residence, a change of country or a complex tax treaty situation.
- All filing obligation thresholds and the rules on exceptional income.
- Eligibility for assimilation to resident taxpayers, the best option for a couple or the amount of any saving.
- How to correct a return after filing or how to challenge a tax assessment notice.
Confidentiality and next step
The diagnostic runs in your browser without transmitting your answers. No amount, name or tax number is requested and no document is collected.
Read the guide to the suggested form and the checklist. If the information is incomplete, a review of your file is the next step; it would be misleading to conclude that no return is required.
The firm’s other tax engagements
Depending on your situation, the firm also handles tax, VAT and payroll, the regularisation of late tax filings and assistance during a tax audit. Fees are listed in the firm’s fee grid.
Official sources and scope
- ACD: assessment based on a tax return
- ACD: annual tax adjustment
- Guichet.lu: annual tax adjustment for residents
- Guichet.lu: annual tax adjustment for non-residents
The rules apply to the year and profile concerned. Examples flagged as fictitious explain a method; they are not an individual validation. The documents and options of your file are covered by a separate engagement.