taxx.lu: how to file your tax return online in Luxembourg
Skimming?
We've prepared the shortcut for you.
What taxx.lu is, in plain terms
taxx.lu (ouvre dans un nouvel onglet) is an online platform that lets you fill in and generate your Luxembourg tax return yourself, without going through an accounting firm. It has existed since 2018, it is run from Luxembourg (the site is part of the atHome group) and it is aimed at residents and cross-border workers alike. taxx.lu presents itself as the leader in online tax filing in the country and claims tens of thousands of users.
In practice, the tool replaces the paper-form headache. You answer questions, the site translates your answers into the right boxes of form 100 (the standard return) or form 163 (the annual statement, simpler), and along the way it works out what you can expect to get back. At the end, you download a document ready to send to the Luxembourg Inland Revenue (Administration des contributions directes, ACD), the tax office. Note that taxx.lu does not file the return for you: you are the one who sends it, via MyGuichet.lu or by post.
How to file your return on taxx.lu, step by step
Create an account and import your documents
First, you create a free account. Then, instead of typing everything by hand, you can import your data. The taxx.lu Scanner app (iPhone and Android) photographs your tax certificates and the Auto Scan feature picks up the amounts automatically. If you already filed last year, you can also import last year's PDF to start with half the work already done.
Complete it, guided step by step
The site asks questions about your situation (employee, cross-border worker, married, children, home loan) and the forms adapt on their own. Deduction ceilings are calculated automatically, so you won't claim more than you're entitled to. If you get stuck, there's a detailed FAQ and support by chat or email.
Check what you'll get back, before paying
This is the smart move: you can fill in your return and simulate your result for free, before any payment. You see whether you'll get tax back or owe some, and how much. Their in-house tool, the Opti-Score, shows your optimisation potential, meaning the deductions you could still activate. You only pay if you decide to generate the final return.
Download it and send it yourself
Once paid, you download your complete return, ready to go. The last step is for you to send it to the tax office, usually via MyGuichet.lu. taxx.lu prepares the document but doesn't file it for you: keep that in mind so you don't miss the deadline.
Who taxx.lu is really useful for
The tool is most useful for people who have things to deduct but no desire to become tax experts. If you're an employee with a home loan, insurance or commuting costs to claim, it helps you recover your overpaid tax without combing through the law. If you're a cross-border worker, it's even more relevant: a return with foreign income and a request for assimilation (the status that gives you access to the same deductions as a resident) is one of the most tedious cases to fill in by hand, and that's exactly where a guided tool saves time. Civil servants, the self-employed and the liberal professions also have dedicated paths.
Where it's less obvious is in two opposite cases. If your situation is very simple and you have nothing special to recover, the free MyGuichet assistant may be enough. And if it's genuinely complex (large assets, income from several countries, a company), a tax adviser is still more suitable than an online form, however well designed.
What it costs
taxx.lu works with three packages (ouvre dans un nouvel onglet) (2026 prices):
- Standard pack at 69 €: you fill in your return on your own, with the optimisation analysis and the annexes generated automatically.
- Plus pack at 119 €: everything in Standard, plus a review of your return by an expert and a check of your tax assessment.
- Premium pack at 199 €: everything in Plus, plus a video call with a tax expert.
taxx.lu or filing yourself on MyGuichet?
That's the real question, because the State already offers a free assistant: on MyGuichet.lu, you can fill in and sign your return online (ouvre dans un nouvel onglet) without paying anything. For a simple situation, it does the job.
The difference is the support. The official assistant follows the administration's logic: it helps you fill in, but it won't tell you where you're giving up money. taxx.lu, on the other hand, is built to spot the deductions you're entitled to and estimate your refund as you go. In short: MyGuichet is free but bare, taxx.lu is paid but holds your hand and aims to optimise. For many people, the time saved and the tax recovered more than cover the price of the package. It's up to you where you set the cursor between saving money and saving time.
First things first: are you even required to file?
A useful step back, because many people approach this the wrong way round. In Luxembourg, salaries and pensions are already taxed at source, so a large share of taxpayers are not required to file a return. You are required, however, in specific cases: for example if your taxable income exceeds 100,000 €, if you receive more than 600 € a year in income not taxed at source (rent, typically), or if you combine several tax cards above certain thresholds. The full details are on Guichet.lu (ouvre dans un nouvel onglet).
But here's the thing: not being required doesn't mean you have no interest in filing. It's often the opposite. If too much tax was withheld from your salary during the year (starting a job mid-year, part-time months, deductions not taken into account), a voluntary return, or a simple annual statement via form 163, lets you recover the difference. In other words, the real question isn't only "do I have to?" but "does the tax office owe me something?". And that's exactly what taxx.lu's free simulation lets you check in a few minutes.
Frequently asked questions
Yes. It's a Luxembourg company (atHome group), active since 2018, which uses encryption and follows Luxembourg data-protection rules. Your tax information stays confidential.
Creating an account and simulating your result is free. You only pay if you generate the final return, from 69 €. The 100% free alternative is the official MyGuichet.lu assistant.
Yes, the tool is designed for cross-border workers, including foreign income and the assimilation request. Note: filing in Luxembourg doesn't exempt you from filing in your country of residence.
Not on its own. You answer the questions, the tool places your answers in the right boxes, calculates the ceilings and spots the deductions. For a real human review, you need a Plus or Premium package.
No. It generates a document ready to send, but you're the one who files it, via MyGuichet.lu or by post to your tax office. Mind the deadline.
A tax adviser analyses your situation in depth and takes on responsibility, which costs more. taxx.lu is a self-service tool, cheaper and great for everyday situations. For a complex wealth situation, the adviser still has the edge.