Cross-border workers in Luxembourg
How many remote working days do you have left?
Cross-border workers may spend a limited number of days working outside Luxembourg without changing how they are taxed. Cross that line and it is not the extra day that becomes taxable at home — it is the whole year. This counter shows you where you stand.
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Remote work, business travel and training outside the Grand Duchy, since 1 January.
Basis for the social security threshold. Around 230 days for full time.
34
Every day counts on its own. One hour started at home uses up a full day.
As long as your share of remote work stays below this mark, you remain covered by the Luxembourg CCSS. This threshold is entirely separate from the tax one.
Three things that catch almost everyone out
Half an hour is a whole day
What counts is physical presence. Work two hours at home in the morning, then drive to the office in Luxembourg, and a full day of your budget is gone. There is no counting by the hour or the half day.
All or nothing
Exceed the threshold by a single day and it is not that one day that becomes taxable at home — it is every day you worked outside Luxembourg that year.
The proof is on you
The burden of proof sits with the taxpayer, not the employer and not the tax office. Employment contract, time records, travel tickets, hotel invoices, mission orders and attendance lists can all be requested. Keep a running record.
A worked example
Anne lives in Thionville and works full time in Kirchberg. By the end of July she had worked 18 days from home, spent 3 days at a training course in Paris and 2 days on a business trip to Brussels.
18 + 3 + 2 = 23 days used. Of her 34, eleven are left for the rest of the year.
At one remote day a week that lasts until mid-October. After that she either goes to the office or crosses the line — and all 34 days become retroactively taxable in France, not only the ones above the threshold.
What counts and what does not
Counts towards the threshold
- Remote work from your country of residence
- Days worked in a third country for your Luxembourg employer
- Business travel outside Luxembourg
- Training attended outside the Grand Duchy
Does not count
- Holiday
- Sick days
- Weekly rest and public holidays not worked
- Force majeure beyond the control of either party
Special cases
Travel to a third country
A working day in Frankfurt or London for your Luxembourg employer counts towards the 34 days exactly like a day at your kitchen table. What matters is not where you live but that you worked outside the Grand Duchy.
Starting mid-year
If you start during the year, the threshold is reduced pro rata. Start in July and it is around 17 days, not 34. The same reduction applies to part-time contracts, and it is always rounded down.
There is no half day
One hour of work at home before you set off? A full day. Counting is based on physical presence, not on hours worked. Regularly starting at home in the morning burns through the budget far faster than people expect.
Two independent systems
Tax and social security follow separate rules. You can be entirely within the social security limit and still be far over the tax threshold. The reverse is rare but possible.
What happens if you go over?
First, to be clear: this is not an offence. Working more than 34 days outside Luxembourg is allowed — it only changes who gets to tax your salary.
- The share of your salary matching every day worked outside Luxembourg becomes taxable in your country of residence.
- You will need a tax return at home, and your employer will usually have to split your pay between the two countries.
- Is it more expensive? That depends on the rate. In some situations it is actually cheaper. There is no general answer — it needs a calculation for your own case.
- Keep your records. Since the burden of proof is on you, your documentation is what decides which number stands if you are audited.
The other way round: Luxembourg resident working from abroad
The 34-day threshold only applies to cross-border workers. Someone living and working in Luxembourg falls outside it entirely — and still asks the same question: what happens if I work two weeks from Italy, Portugal or Spain? That runs on a different set of rules.
Rarely a tax problem
As a Luxembourg tax resident you are taxed in Luxembourg on your worldwide income. The other country normally only steps in beyond 183 days of presence in the year, or if your employer has a permanent establishment there or bears the salary cost. Two weeks of working by the sea therefore changes nothing as a rule.
The A1 certificate is almost always missing
The moment you work in another EU country for your Luxembourg employer, you need an A1 certificate from the CCSS — in principle from day one. It proves you remain covered in Luxembourg. Without it you are formally uncovered in an inspection, and several countries now actively check remote work.
The EU framework agreement does not help here
The 49.9 % limit only covers telework carried out from your country of residence. If you live in Luxembourg and work from Italy, Italy is a third country: legally this is a posting, not remote work, and different rules apply.
The bigger risk sits with the employer
When employees work from abroad for longer periods and possibly develop business there, a permanent establishment can arise — bringing corporate tax liability in that country. Many companies therefore set firm caps on working from abroad. Ask HR before you book.
Keep a record
Since the burden of proof is on you, a dated record beats a memory. Print your position or email it to yourself.
For printing, nothing leaves your browser. For email, the figures, name and employer are sent once to our server, laid out as a PDF and dispatched — none of it is stored, not even the email address.
Get an alert
We will let you know if the rule changes — and, if you want, as soon as you approach your personal threshold. No advertising, unsubscribe any time.
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Common questions
How many remote working days are allowed?
For cross-border workers resident in France, Belgium and Germany the tolerance threshold is a uniform 34 days per year outside Luxembourg. Below that, the entire salary stays taxable in Luxembourg.
What happens if I go over?
The right to tax every day worked outside Luxembourg moves to your country of residence, not just the days above the threshold. That can mean a tax return at home and a split of your salary between two countries.
What does social security have to do with it?
Nothing — and that is the most common misunderstanding. For social security you may work up to 49.9 % of your working time from home and still stay with the Luxembourg CCSS, which is roughly 110 days depending on your contract. The 34-day tax threshold sits far below that and applies independently.
Could the number 34 change?
Possibly. Luxembourg and its neighbours have been negotiating an increase for some time. Until something is ratified, the current rule applies. We update this page as soon as anything changes.
Who should keep count?
Anyone regularly working outside Luxembourg for a Luxembourg employer. Since the burden of proof falls on the employee, a record kept through the year is far safer than a reconstruction in December.
I live in Luxembourg — does the 34-day threshold apply to me?
No. It only concerns cross-border workers resident in France, Belgium or Germany. A Luxembourg resident is taxed in Luxembourg anyway. If you work temporarily from another country, what you need instead is an A1 certificate from the CCSS, and beyond roughly 183 days of presence the other country may become competent for tax.
Underlying rules
The information on this page is based on the following:
- Circular of the Luxembourg director of taxation of 24 June 2026 on how the 34 days are counted
- Amendment to the Luxembourg–France tax treaty, in force since 1 January 2023, ratified in February 2025
- Luxembourg–Belgium agreement, ratified 22 December 2022, retroactive to 1 January 2022
- Tolerance threshold with Germany, raised from 19 to 34 days on 1 January 2024
- European framework agreement on teleworking of July 2023 (49.9 % limit for social security)
Who runs this site
homeoffice.lu is run by iSOLUTIONS S.à r.l., a company registered in Luxembourg (RCS B84137). We are not tax advisers. This site summarises publicly available rules and does the arithmetic for you — it does not replace advice on your own situation.
Found a mistake, or has a rule changed? Write to hello@homeoffice.lu.
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