Expense reports in Odoo: managing and booking employee expenses in Luxembourg

In short. The Odoo expenses module covers the whole journey of an employee expense: photograph the receipt, submit, approve, reimburse and post the accounting entry. For a Luxembourg SME, the hard part is not data entry but the booking: the right expense accounts under the PCN 2020, VAT handled correctly, and supporting documents you can actually find during an audit.

A poorly managed expense claim costs you twice. First the time spent chasing till receipts, then the accountant's time rebuilding the expense at month end. The Odoo expenses module removes most of that friction, provided you configure it with the end in mind: your Luxembourg accounting.

What does the Odoo expenses module do?

The Expenses app lets every employee photograph a receipt from their phone, create the expense in a few fields and submit it for approval. Once approved, the expense generates the accounting entry and triggers the reimbursement, with no re-keying on the accounting side.

In the Enterprise edition, receipt digitization extracts the amount, date and vendor from the photographed ticket. Every expense belongs to a category (meals, travel, accommodation, small equipment), and the category is what carries the expense account and the tax. All the configuration that matters happens there.

From receipt to reimbursement: the full workflow

1. Capture

The employee photographs the receipt in the mobile app or forwards the invoice by email to a dedicated address. They pick the category, state whether the expense was paid out of pocket or with a company payment method, and submit. The supporting document stays attached to the expense, which puts an end to envelopes of receipts sleeping in a drawer.

2. Approval

The manager receives the claims to approve, one by one or grouped in a report. This is the right place to enforce your internal rules: a cap per meal, a mandatory receipt above a given amount, a documented refusal. A written rule applied in the tool beats an oral tolerance nobody dares to challenge.

3. Booking and reimbursement

On approval, Odoo posts the entry: expense on the debit side, a liability towards the employee on the credit side. Reimbursement then goes out like a regular vendor payment, or through payroll if you prefer to bundle it with salaries. On that second option, keep in mind that Luxembourg payroll in Odoo needs a complement: direct bank transfer remains the simplest circuit for an SME.

Booking expenses under Luxembourg rules

Each expense category must point to the right class 6 expense account of the PCN 2020, the standard chart of accounts for Luxembourg companies. This mapping is done once, at configuration time, and everything downstream depends on it: if business meals and travel land in the same catch-all account, your P&L loses readability and your fiduciary wastes time reclassifying. The prerequisite is a properly deployed chart of accounts; we cover that foundation in our guide to setting up Luxembourg accounting in Odoo.

Another benefit, often discovered during an audit: every expense entry keeps its digitized receipt attached. When the tax authorities request a FAIA audit file, the supporting document is two clicks away instead of a three-year-old ticket hunt.

VAT on expense reports: what to configure

In Luxembourg, VAT paid on an expense incurred for business purposes is in principle deductible, provided you hold a compliant invoice. The rate depends on the nature of the expense: 17% standard, or 14%, 8% and 3% reduced rates depending on the case (as of July 2026). Configure the tax directly on the expense category, so the amounts flow correctly into the VAT return prepared in Odoo.

Watch the borderline cases: entertainment costs, business gifts, expenses with mixed private and business use. Deduction rules there are specific, and mistakes surface during audits. A bare till receipt without the required details is not always enough to support the deduction. When in doubt, have your accountant validate the treatment rather than deducting by default.

A concrete case

A services firm of eight people we support on their accounting (anonymized) used to manage expenses with a spreadsheet and stapled receipts. The result: half a day of bookkeeping every month and VAT deducted inconsistently. After activating the expenses module, mapping the categories to the PCN 2020 and writing three simple internal rules, the monthly expense close takes under an hour and the VAT treatment is uniform. No custom development was needed.

FAQ

How is an expense report booked?

The expense is recorded as a cost (class 6 of the PCN 2020) with, as counterpart, a liability towards the employee who advanced the money. In Odoo this entry is generated automatically on approval, using the account configured on the expense category.

Which supporting documents should be kept?

The original invoice or receipt, with the details identifying the supplier, the date and the amount. Digitizing in Odoo makes archiving and audits easier, but check with your accountant which retention policy for paper originals fits your situation.

Can VAT be recovered on expense reports?

In principle yes, if the expense is business-related and the invoice compliant. Some categories (entertainment, gifts, mixed use) follow specific rules. Setting the tax on each expense category in Odoo applies the right treatment systematically.

Can reimbursement go through payroll?

Odoo supports it, but since Luxembourg payroll usually requires a complementary tool, reimbursement by bank transfer, handled like a vendor payment, remains the simplest and most traceable circuit for an SME in Luxembourg.

Why Advena?

• Clear packages, no hourly billing: you know what you pay, right from the start.
• Finance and digital under one roof: the module is configured by people who know the PCN 2020, not just the software.
• ROI first: every recommendation is justified by its concrete return.
• Direct access to the founders: the partners work with you.

Going further: Setting up Luxembourg accounting in Odoo · Luxembourg VAT returns in Odoo · Odoo and payroll in Luxembourg · Odoo in Luxembourg: the right ERP for your SME?