Missing the monthly VAT return deadline — which falls strictly before the 15th of the following month — exposes a Luxembourg company to financial penalties. The tax on turnover is collected by the Administration de l’enregistrement, des domaines et de la TVA (AED), and missing their cut-off is a frequent compliance failure for new founders. Because the administration legally provides the monthly regime by default, most companies start here unless reassigned. The AED decides the regime.
This specific schedule binds companies placed on that default monthly regime, alongside those generating an annual turnover above six hundred and twenty thousand euros. It does not apply to businesses assigned to the quarterly or annual regimes, which carry their own distinct deadlines. A company operating under the small business franchise — meaning its turnover stays below fifty thousand euros — is entirely exempt from these periodic returns, provided no specific cross-border conditions pull it back into the reporting net.
The compliance calendar mixes fixed days and rolling months
A founder on the monthly regime manages this deadline alongside a wider set of corporate duties. The dates remain static, but they operate on entirely different clocks. For direct taxes, the ACD sets the deadline at 31 December of the year following the tax year.
| Obligation | Cut-off |
|---|---|
| Monthly VAT return | Due: monthly / quarterly returns due before the 15th of the month following the period, filed electronically via eCDF |
| Corporate income tax return | Due: 31 December of the year following the tax year |
| RBE declaration | 1 month after registration |
| Annual general meeting | 6 months after financial year-end |
The wording of the deadline silently shifts the final day
What actually goes wrong in practice at this deadline is misreading the preposition. The official rule requires the return to be filed before the 15th of the month following the period. Founders who diary the 15th as the filing day find themselves late when they hit send, because the legal window closed at midnight on the fourteenth. The 15th is too late. The administration treats a submission on the 15th exactly as it treats one weeks later.
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Since the first of January two thousand and twenty, every return must be deposited by electronic transfer — either by entering an online form or transferring an XML file via the eCDF platform. Paper forms are rejected, and the administration does not accept files attached to an email. Setting up the digital environment for filing tax and VAT returns in Luxembourg through eCDF and MyGuichet is a separate task from calculating the tax itself.
The electronic filing sequence strictly dictates the workflow
Because the transmission is entirely digital, the work happens in a set order that cannot be compressed into a single afternoon. If a founder delegates their accounting and tax filings — a service that runs from €250 a month — the external firm operates within this exact sequence.
See what monthly accounting includes, from €250- Register the account. The user must first register on the eCDF platform to create an active profile.
- Format the data. The return takes the shape of an online form entry or an XML file transfer.
- Transmit the file. The data moves through the eCDF system directly to the tax authority.
The platform dictates the timeline, and a founder without an active account on the fourteenth cannot generate one in time to file before the 15th.
Figures verified against guichet.public.lu, guichet.public.lu, guichet.public.lu, guichet.public.lu, guichet.public.lu on 2026-10-23.