Bookkeeping requirements in Luxembourg: what you keep, for how long, and where

A Luxembourg company must keep its accounting books and every document behind them for 10 years, in Luxembourg, on paper or electronically. Invoices issued and received carry the same 10-year period, counted from the issue date.

From those records the company produces annual accounts, approved by the shareholders within 6 months of the financial year end and filed within 7 months. For the tax office it produces a single return (modèle 500) covering corporate income tax, municipal business tax and net wealth tax.

Retention periods and the electronic-filing rules below were verified in August 2026 against guichet.public.lu on accounting obligations, the AED's obligations for taxable persons, and the Administration des contributions directes on electronic filing. The corporate and VAT return dates carry their own official links where they appear below. The 7-month accounts deadline sits in company law rather than on any of those tax pages, and both of its legs are set out in full further down.

What you keep, and for how long

The duty is not "keep your invoices". Every entry in the books has to trace back to a document, and the document has to still exist years after everyone involved has moved on. Bookkeeping without documents is storytelling. Only one of these periods has an explicit starting point: the invoice clock runs from the date on the invoice itself, not from the year-end.

Electronic storage is fully acceptable. What the rule actually asks is that integrity and readability survive the whole period, which in practice means organised, backed-up files rather than an inbox you intend to search one day.

Notice that the obligation is stated as a place. The records live in Luxembourg. For a company run from abroad that is a design constraint rather than a formality, because the files have to be producible at the Luxembourg seat and not only on a laptop in another country. Winding the company up shortens the duty without cancelling it. In a liquidation the period drops to 5 years, and somebody still has to be holding the box.

What the books have to produce

Three things leave the company each year, and all three are drawn from the same ledger. If the ledger is clean, they are mechanical; if it is not, each one becomes its own reconstruction project. Two of them run on a clock the company sets itself, its financial year end, while the tax return runs on a fixed calendar date. They feel unrelated right up until the first close puts them in the same fortnight.

The 7-month figure is two clocks in sequence rather than one deadline. The shareholders meet and approve the accounts within 6 months of the financial year end; the approved set is then filed within 1 month. Put the 6-month date in the calendar, because it is the one that needs other people: a finished set of accounts, and shareholders willing to sign them off.

The filing that follows is an administrative act you control alone. The accounts are prepared on the standard national chart of accounts, submitted electronically through eCDF, and deposited with the Trade and Companies Register through the LBR portal, where they become public.

On the tax side the same ledger feeds one return rather than three, and electronic filing is mandatory via MyGuichet.lu since tax year 2017 for resident capital companies, including the s.à r.l. and the s.à r.l.-S. VAT sets the working rhythm in between. A company that books monthly has already done the work each VAT return asks for; a company that books once a year does that same work over again, from memory.

Size class: abridged accounts, or a statutory audit

Luxembourg sorts companies into size classes, and the class decides two things: how much of the accounts the company puts on the public record, and whether an independent auditor has to sign them.

A small company files an abridged set — a shortened balance sheet and profit-and-loss account, with most of the detail kept out of the register. Move up a class and disclosure widens, and a statutory audit by a réviseur d'entreprises agréé becomes part of the annual cycle rather than an option.

Three criteria decide the class: balance sheet total, net turnover, and the average number of full-time employees over the financial year.

These limits are higher than the ones most secondary sources still print. They were raised by the règlement grand-ducal of 25 October 2024, which applies to financial years beginning on or after 1 January 2023. The small-company balance-sheet limit moved from €4,400,000 and the turnover limit from €8,800,000. A guide quoting the older pair is describing financial years that have already closed.

The class does not flip on one unusual year: crossing the limits of two of the three criteria only changes a company's size class if it happens at two consecutive balance-sheet dates. That repetition rule is the useful part in practice, because it makes the change visible a full year before it bites.

A company watching its own three numbers at each close can see an audit coming and plan for it, rather than discovering in the closing weeks that this year's accounts cannot be filed without a réviseur. The auditor has to be appointed, and the audit itself needs lead time.

There is no separate euro figure for the audit itself: companies that stay within the article 35 small-company limits are exempt from appointing a réviseur d'entreprises agréé, so the audit is triggered by exceeding two of those three criteria. The small-company table above is the audit test, read the other way round.

What actually goes wrong

The failures here are rarely conceptual. Nobody misunderstands that records have to be kept. The problems are logistical, and they share a shape: invisible while the year is running, expensive in the fortnight before a filing date. All four below are cheap to prevent at setup and awkward to fix under time pressure.

The chart of accounts. Books kept in a foreign accounting tool on its default plan have to be mapped onto Luxembourg's standard chart before anything can be filed. Done at setup, that mapping costs an afternoon. Left until the closing weeks of the 7-month window, it becomes a re-posting of a full year under deadline, which is how a first close quietly turns into a late one.

The signature nobody arranged. The tax return cannot be filed without the credential to sign it: a LuxTrust product (private or pro) is required both to use MyGuichet and to sign the return. It is easy to miss because nothing in the bookkeeping year prompts it.

This is an identity task sitting in the middle of an accounting process, and the verification behind a LuxTrust product takes days rather than minutes. Order it in the first month, not in the week you planned to file.

Late filing at the register is public. The annual accounts land in a public register, so a missing deposit is visible to any bank, landlord or counterparty that looks the company up. A bank's compliance team does look, before opening an account and again before renewing one. Late tax returns cost money more directly: a supplement of up to 10% of the tax assessed can be applied for a return filed out of time.

Reconstruction. The company that books once a year is not saving the work; it is deferring it into the month with the least slack and paying for the memory that has evaporated in the meantime. Every mixed personal expense and every unexplained transfer becomes a question asked a year too late.

The habits that make this cheap

Compliance asks almost exactly the same things of two similar companies and costs them very different amounts of effort. The difference is not the rules and not the software. It is how much reconstruction has to happen before a close can even start: how many transactions still need a document found, a category decided, or a memory consulted. Four habits remove most of that, and all four spend attention during the year instead of time at the end of it.

1. Separate everything. One business account, zero personal expenses running through it. Every mixed transaction creates future work and, at year-end, an argument about deductibility.
2. Capture documents at the moment they exist. A photo or PDF filed the day a receipt appears costs seconds. The same receipt hunted in February costs minutes and sometimes the deduction.
3. Book monthly. Volume stays manageable, memory stays fresh, and VAT filings draw on current data instead of archaeology.
4. Reconcile the bank. If books and bank agree every month, the year-end close is a formality. If they diverge for a year, the close is an investigation.

Common questions

Can I do my own bookkeeping?

Yes, in law. The company's managers answer for the accounts whoever holds the pen, because the law fixes responsibility rather than who does the data entry, and nothing obliges a small company to outsource its ledger.

The constraint is economic rather than legal: the work is repetitive, it has to be right on a fixed date, and it competes hour for hour with the work that produces revenue. A mistake in it also compounds silently for eleven months and surfaces at the close, when it is most expensive to unpick.

Does a dormant company still have to file?

Yes. The obligation attaches to the company, not to its turnover: a year with no invoices still produces annual accounts, still needs them approved within 6 months and filed within 7 months, and still produces a tax return. The minimum net wealth tax also runs regardless of profit, at €535 a year on a balance sheet up to €350,000.

Can I keep my records in English, or on a foreign cloud service?

Two questions with two different answers. On language, what is prescribed is the form of the output, not the language of your day-to-day ledger. The annual accounts are filed on the standard national chart of accounts through eCDF, and the tax return goes in on the modèle 500 templates, so the statutory deliverables come out in Luxembourg's own format whatever language you booked in.

On the cloud service, what is prescribed is the place. The records are kept in Luxembourg, which is a statement about where the complete books and their supporting documents must be producible, not about which company hosts the software. A foreign tool is workable on that basis; what fails is a tool you no longer pay for.

Access, not storage, is the weak point — an accounting subscription that closes at the end of a contract takes the archive with it, and the duty still has years left to run. Export a full, readable copy at every close and keep it where the books are kept.

How long do I keep an invoice I received from a supplier?

10 years from its issue date, exactly as for invoices you issue. It must also meet the formal requirements to support the VAT you deduct on it.

The first year, in order

Sequence matters more than effort here. Each step below removes a task from the month the deadlines land in. The first three are done once, in the opening weeks, while there is no volume to make them painful; steps four to six recur, and they are only cheap because the first three happened.

1. Open the business account before the first transaction, and never let a personal expense through it.
2. Set the ledger up on the Luxembourg chart of accounts at the start, rather than remapping a foreign default plan under deadline.
3. Order the LuxTrust product in the first month, because it is what signs the tax return and what gets you into MyGuichet, and the identity verification behind it takes days rather than minutes.
4. Close and reconcile every month, so that each VAT return is a read-out rather than a project.
5. Put all three annual dates in the calendar: the shareholders' approval within 6 months of year-end, the filing within 7 months, and the return by 31 December of the year following the tax year.
6. File the supporting documents as you go and keep the archive for 10 years, in Luxembourg, in a form that will still open at the end of that period.