Tax in Luxembourg, properly explained
How residents and non-residents are taxed — classes, declarations, deductions, cross-border days, impatriate scheme.
Luxembourg income tax is administered by the ACD (Administration des Contributions Directes). Tax residents are taxed on worldwide income; non-residents are taxed on Luxembourg-source income. The progressive scale, the tax class system (1, 1a, 2) and the way employer-withheld tax interacts with the annual declaration (form 100) are the four ideas to anchor on.
The system is built around the fiscal household and the marital or PACS status — that is why getting your tax class right matters more here than in many countries. A single bracket structure applies to everyone, but the bracket boundaries shift with the class, so the same gross salary will produce a materially different net depending on whether you are taxed as a single person, as a single parent or as a married couple opting for joint filing. The reform of 2018 also added pure individual taxation as an option for married households, which changed the maths for dual-career couples.
Three guides below break down the parts most people get wrong: the class system itself, the cross-border rules for residents of France, Belgium and Germany, and the impatriate regime designed to attract talent from abroad. If you are reading a payslip for the first time, start with the payslip explainer; if you are opening your first account, start with opening a bank account.
Three guides in this topic
Built around the three questions newcomers and cross-border workers run into in their first year.
Tax classes 1, 1a and 2
How marital status and residency drive the class on your tax card — and how joint or separate taxation changes the bill for married households.
Cross-border tax (FR, BE, DE)
How the bilateral conventions, day thresholds and EU social-security regulation 883/2004 interact for residents of France, Belgium and Germany.
The impatriate regime
The opt-in scheme for highly qualified hires from abroad — what it covers, who qualifies and why it has to be written into the contract.
Opening a bank account
Cross-link: you need a Luxembourg IBAN to receive a salary and for the ACD to refund you. The realistic path for non-residents and new arrivals.
Reading a Luxembourg payslip
Cross-link: the line-by-line breakdown of CCSS, FNS, dependency contribution and the income-tax retained at source. Where every euro goes.
What's covered in this section
The four ideas to anchor on. Everything else in the topic builds on one of these.
Resident vs non-resident
Worldwide income vs Luxembourg-source income. The six-month rule, the fiscal domicile concept, and how cross-border workers are treated separately.
Tax classes & brackets
One progressive scale, three class entry points (1, 1a, 2). The class on your tax card drives the monthly retention; the annual form 100 reconciles.
Deductions and credits
Pension contributions, housing-loan interest, charitable giving, childcare, alimony, professional expenses (frais d'obtention) — what actually moves the needle.
Cross-border framework
Day thresholds in the LU-FR, LU-BE and LU-DE conventions; EU 883/2004 for social security; the framework agreement on telework signed by the three neighbours.
Related guides across the site.
Tax classes 1, 1a and 2
How marital status, residency and the choice between joint and separate filing drive the bill.
Tax · Cross-borderCross-border tax: FR, BE, DE
Day thresholds, social-security framework, filing in two countries.
TaxThe impatriate regime
Opt-in scheme for senior hires from abroad — what it covers and who qualifies.
WorkReading a Luxembourg payslip
CCSS, FNS, dependency contribution and tax at source, line by line.
MoneyOpening a bank account
Which banks accept non-residents, documents to bring, realistic timelines.
Cross-borderFrom France
The 2023 amended convention, the 34-day tolerance and what it means in practice.
Tax in Luxembourg — frequently asked.
Each answer links to the full guide for the detail.
When am I considered a tax resident?
You are a Luxembourg tax resident if you have your fiscal domicile or your habitual abode in the country. In practice the ACD treats anyone who lives in Luxembourg for more than six months in a year as a resident, with the period straddling two calendar years. Residents are taxed on worldwide income; non-residents only on Luxembourg-source income. More on classes and residency →
Do I file even if my employer withholds tax?
Often yes. The employer-withheld tax is an advance based on your tax card. The annual declaration (form 100) reconciles it against your real situation — extra income, deductions, household composition, charity, cross-border days. Filing is mandatory in many cases and almost always advantageous when you have deductible expenses. See the payslip walk-through →
How do I get into tax class 2?
Class 2 is granted to married couples and to civil partners (PACSed) who request it and meet the conditions. Widowed taxpayers keep class 2 for a defined period after the death of the spouse. Non-residents need to meet the assimilation conditions (broadly, at least 90% of worldwide household income taxed in Luxembourg) to opt in. Full class breakdown →
Is the impatriate regime worth it?
For senior hires from abroad, it usually is — provided the contract was structured around it from day one. The regime exempts specific categories of expense (moving, housing differential, school fees, home leave) from taxable income. It is opt-in via the contract: if it is not stated there, you do not benefit from it. Read the impatriate guide →
How does the cross-border tax work?
Employment income is taxed where the work is physically performed. Each of France, Belgium and Germany has its own tolerance for days worked outside Luxembourg before the home country can tax the corresponding share. Social security stays with Luxembourg under EU 883/2004 as long as less than 25% of the work is done in the country of residence — with the EU framework agreement on telework loosening that to up to 49.99% for participating countries. Full framework →
Do I file with my spouse?
Since the 2018 reform, married couples can choose between joint filing (imposition collective) and pure individual filing (imposition individuelle pure). Joint filing tends to favour single-earner households; individual filing can favour two-earner households with similar incomes. The choice is made annually on the form 100. Joint vs separate, in detail →
Tax is one of four interlocking topics
Tax does not stand alone. It is the visible end of the social-insurance system administered through the payslip by the CCSS; it determines how much net hits the account you opened under the money guides; and for half the country's workforce it sits on top of a cross-border framework that depends on which side of the border you sleep on. The three guides below are the deepest entry points; the rest of the site fills in the practical detail around them.
Written from the legal source, not the LinkedIn summary.
Every tax page on World.lu cites the LIR (loi du 4 décembre 1967 sur l'impôt sur le revenu), the relevant ACD circular, the bilateral convention article, or the Guichet.lu page that summarises the procedure. Brackets and thresholds are intentionally not stated in current-year figures: they move, and out-of-date numbers are worse than no numbers. Where you see [verify], the principle is stable but the exact figure should be confirmed against the cited source.