Deductible business expenses in Luxembourg: what qualifies and what doesn't

Short version. An expense is deductible from a Luxembourg company's taxable profit when it is an operating expense, meaning an expense caused exclusively by the company's activity. The principle is broad, but article 168 of the Income Tax Law (LIR) expressly excludes some: corporate income tax, municipal business tax, net wealth tax, directors' fees, fines and private-purpose spending. Classifying these correctly is what separates a fair taxable profit from tax paid for nothing.

"Can I put it through the business?" comes up in almost every conversation with an SME owner. The answer rests on one simple rule and a list of exceptions. The trouble is that the rule is widely misunderstood (deductible does not mean free) and the exceptions are rarely cited from an official source. Here is the full mechanism, with the list of non-deductible expenses exactly as the Direct Tax Authority publishes it, and the grey areas that spark debate.

What counts as a deductible expense in Luxembourg?

An expense is deductible in Luxembourg when it is an operating expense, meaning an expense caused exclusively by the business. Three conditions follow from that definition: the expense must be incurred in the interest of the activity, be real and backed by a document, and relate to the financial year concerned. An expense incurred for the owner's private benefit does not qualify, even if it runs through the company's account.

The principle therefore favours the taxpayer: anything that genuinely serves the activity is in principle deductible. What matters is the burden of proof. Without an invoice in the company's name and without supporting evidence, an otherwise legitimate expense becomes contestable in a tax audit. Deductibility is not decided at year-end; it is built document by document throughout the year.

Commonly deductible expenses

Provided they are incurred for the activity and documented, these expenses reduce taxable profit:

• purchases of goods, raw materials and supplies;
• gross salaries and employer social contributions;
• rent and running costs of business premises;
• professional fees (accountant, lawyer, consultant, IT);
• business insurance;
• bank charges and interest on loans taken out for the business;
• energy, telecoms and software subscriptions;
• depreciation of fixed assets, spread over their useful life;
• professional training, small equipment and business travel.

Two useful clarifications. A durable investment (a vehicle, furniture, a machine) is not deducted in one go: it is depreciated over several years under the standard chart of accounts (PCN 2020). And an expense straddling two years, such as an annual insurance premium paid in advance, must be matched to the correct year through an adjustment entry. These are closing adjustments, not details.

The expenses the law expressly excludes

This is the part you rarely find online. Article 168 LIR lists the expenses that do not qualify as operating expenses. For a capital company (Sàrl, SA, Sàrl-S), the main ones are as follows.

The full list is on the non-deductible operating expenses page of the Direct Tax Authority (position as at July 2026). Two points deserve emphasis. First, a company's three taxes (IRC, ICC and net wealth tax) are never deducted from its own taxable profit: this is a classic error in accounts reconstructed at year-end. We set out how they are calculated in our article on corporate tax in Luxembourg. Second, directors' fees paid to board members are not deductible, whereas the salary of a manager who works in the company is: the distinction is subtle and often confused.

The grey areas, where deductibility is up for debate

Between the plainly deductible business rent and the plainly excluded parking fine lies a band of mixed expenses where the business share and the private share coexist. That is where the relationship with the tax authority plays out.

The car

A car used both for the business and privately is not treated as a simple expense. If it is made available to a manager or an employee, it generates a taxable benefit in kind, and VAT recovery follows its own rules. We devote a full article to the company car in Luxembourg.

Entertainment and hospitality

A business meal, a client gift, an event: these are deductible when they genuinely serve the activity and are documented (date, guest, business reason). The authority stays alert to any element of personal convenience creeping in. A precise record beats an anonymous restaurant receipt.

The home office

When part of a home is genuinely used for the activity, the corresponding share of costs can be taken on, provided it rests on a defensible allocation key (dedicated floor area, use). Whatever belongs to the household's way of life stays excluded by article 168.

Clothing

Only clothing specific to the activity (safety gear, identifiable workwear) is deductible. A suit or everyday outfit, wearable outside work, is not, even if bought for a business meeting.

Deductible does not mean free

This is the most expensive misunderstanding. Putting an expense "through the business" does not make it free: it only reduces taxable profit, and therefore the tax charged on it. For a company based in Luxembourg City, the overall rate on profits is around 24%. In other words, every euro of genuinely deductible expense saves you about 24 cents of tax, not a full euro.

The consequence is simple: buying something you do not need "to put it through the business" always costs you 76 cents net per euro spent. A deduction is a mechanism that lightens a useful expense, never a reason to spend. Conversely, failing to deduct a legitimate expense, for lack of an invoice in the company's name or because it was never booked, means paying tax that was not due. It is this second pitfall, far more common, that really weighs on SMEs.

How continuous bookkeeping maximises your deductions

The difference between a company that deducts everything it is entitled to and one that lets expenses slip is not about clever schemes, but about the rigour of the bookkeeping. Three concrete levers: each purchase invoice is matched to the right PCN 2020 account and the right year; each supporting document is kept and linked to its entry; and depreciation, provisions and closing adjustments are booked at the right moment, not reconstructed six months later.

That is exactly what real-time bookkeeping changes, as opposed to an annual catch-up. At Advena, we keep your books in the Odoo we deployed for you: the purchase invoice scanned today is allocated today, and your taxable result builds up as you go. You see your margin and your provisional tax during the year, instead of discovering them at the close. It is the heart of our approach as an accounting firm in Luxembourg.

One honest caveat

The deductibility of an expense is assessed case by case, and the line between business and private depends on the facts. This article informs and gives you bearings; it does not replace a review of your situation or formal tax advice. We will always tell you plainly when an expense is too fragile to deduct without risk: a slightly higher taxable profit beats a reassessment with interest. And if your file involves complex structures or transfer pricing, that is not our ground, and we will say so at the first meeting.

Frequently asked questions

Which expenses are deductible for a company in Luxembourg?

All operating expenses, meaning those caused by the activity and backed by a document: purchases, salaries and social contributions, business rent, professional fees, insurance, interest on business loans, energy, depreciation, training and business travel. The principle is broad, subject to the exclusions in article 168 LIR.

Is the tax paid by the company deductible?

No. Corporate income tax, municipal business tax and net wealth tax are never deductible from the company's taxable profit, under article 168 LIR. It is a common error in accounts reconstructed at year-end.

Is a business meal or a client gift deductible?

Yes, if it genuinely serves the activity and is documented (date, recipient, business reason). The authority watches the element of personal convenience. A detailed record is essential; a bare restaurant receipt with no context is weak.

Can a fine or penalty be deducted?

No. Fines, confiscations, settlements and other penalties borne by the taxpayer are expressly excluded by article 168 LIR, whatever their origin.

Does "putting it through the business" make a purchase cheaper?

No. A deductible expense reduces taxable profit, and therefore tax, by the tax rate (around 24% in Luxembourg City). An unnecessary purchase put through the business still costs about 76 cents net per euro. A deduction lightens a useful expense; it never makes it free.

Further reading

• Corporate tax in Luxembourg: CIT, municipal business tax and net wealth tax
• Accounting firm in Luxembourg: the complete guide for an SME
• What an accounting firm costs in Luxembourg: fixed fee, hourly rates and hidden extras
• Company car in Luxembourg: benefit in kind and VAT
• Luxembourg VAT returns in Odoo

Why Advena?

• Nothing slips through: each invoice is allocated to the right PCN 2020 account and the right year, so you deduct everything you are entitled to.
• Real-time bookkeeping: your taxable result builds up during the year, in the Odoo we deployed, not in a year-end catch-up.
• A clear flat fee, from €325 per month: bookkeeping, VAT, annual accounts and filings included, with no hourly billing.
• We inform, we do not invent: when an expense is too fragile to deduct, we tell you before the audit.

Information up to date as at July 2026, based on the "non-deductible operating expenses" page of the Direct Tax Authority and the amended Income Tax Law of 4 December 1967 (article 168). This article informs and does not constitute tax advice.