As long as the European application is pending before the EPO, a single clear rule applies. On grant, that clarity fragments into 39 national regimes — and they diverge on precisely the point most easily overlooked in docketing: the due date itself.
The starting point: Rule 51(1) EPC as a deceptive habit
For the European patent application the position is unambiguous. Under Rule 51(1) EPC, a renewal fee falls due “on the last day of the month containing the anniversary of the date of filing of the European patent application”. A filing date of 9 October means a due date of 31 October. Where the filing date falls on 31 May, the due date remains 31 May. The renewal fee for the third year is the first payable (Art. 86(1) EPC) and falls due on the last day of the month containing the second anniversary of filing.
The rule is generous: on average it hands the applicant a little over two weeks. And that is exactly where the trap lies. Anyone who has worked to the end of the month for years tends to carry that habit unexamined into the national phases after grant — and is wrong in roughly a third of the contracting states.
The break at grant: Art. 141 EPC
The obligation to pay renewal fees to the EPO terminates with the payment of the fee due for the year in which the mention of grant is published (Art. 86(2) EPC). Under Art. 141 EPC, national renewal fees may only be imposed for the years following that year. From that moment national law governs exclusively — including the national due date rule, the national period of grace and the national surcharge.
The European bundle patent is therefore also a bundle of deadlines. Validate in ten states and, from grant onwards, you are administering ten deadlines which all derive from the same filing date but do not all fall on the same day.
Group 1: due on the last day of the month of filing
The majority of contracting states follow the pattern of Rule 51(1) EPC. On the sources reviewed, these are:
Albania, Austria, Belgium, Denmark, Estonia, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Latvia, Liechtenstein, Luxembourg, Malta, Monaco, the Netherlands, Norway, San Marino, Spain, Sweden, Switzerland and the United Kingdom.
For Germany this follows directly from § 3(2) PatKostG: the renewal fee falls due “on expiry of the month whose designation corresponds to the month into which the filing date falls”. Austria applies the same approach, the Austrian Patent Office expressly referring to the last day of the month of filing. For France the same result follows from Art. R613-46 CPI; for Switzerland and Liechtenstein from the common territory of protection under the Patent Protection Treaty.
What is striking about this group is how heterogeneous it is. It contains both the classic high-volume validation states and micro-states such as Monaco and San Marino. There is no geographic or legal-family pattern to fall back on.
Group 2: due on the anniversary of the filing date
The second group works to the calendar anniversary — so the deadline expires, on average, a good two weeks earlier than in Group 1. On the sources reviewed, these are:
Bulgaria, Croatia, the Czech Republic, Hungary, Montenegro, North Macedonia, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia and Türkiye.
For Montenegro this follows directly from the statute: Art. 81(2) of the Montenegrin Law on Patents (Official Gazette No. 42/2015, 2/2017, 146/2021, 3/2023) provides that the fees are payable for the third year and each subsequent year and “shall be due on the anniversary of the date of filing of the application”. Art. 81(4) grants an additional period of six months against payment of a surcharge.
The concentration in Central, Eastern and South-Eastern Europe is notable. Portugal and Türkiye are the outliers, to the west and south-east respectively. A portfolio validated predominantly in Western Europe encounters this group rarely — and is caught out by it all the more reliably as soon as a Polish or Czech validation is added.
Two cases that fit neither group
Cyprus. Cyprus has no due date in the continental sense at all. Rule 41(1)(a) of the Patent Regulations of 1998 does not fix a date on which the fee becomes due; it fixes a window within which it must be paid: Form P.13 together with the annual fee is to be filed “within three months before the expiration” of the current year of protection, counted from the filing date. For validated European patents this applies by analogy under Rule 55(1), the years being counted from the filing date of the European application (Rule 55(2)).
Two consequences follow. First, the payment period ends with the expiry of the current year of protection — and that is the day before the anniversary. A right filed on 1 February 2020 completed its first year of protection on 31 January 2021; the widely quoted “due the day before the anniversary” is therefore correct as a docketing date, but it describes the legal effect rather than the drafting technique. Second, there is a three-month payment window: payment cannot validly be made more than three months before the year of protection expires. Paying unusually far in advance risks not lateness but prematurity. The period of grace is six months against a surcharge (Rule 41(1)(b)).
Lithuania. Lithuania follows a different scheme altogether: the maintenance fee is payable within the final two months of the current year of protection, rather than on a date derived from the filing date. Secondary sources are inconsistent here; the Lithuanian Patent Law should be checked before the deadline is docketed.
A point of terminology
The commonly heard formulation that in certain states the renewal fee is payable “on the filing date” is misleading and should be kept out of docketing instructions. What is meant is always the anniversary of the filing date — the same calendar day in a later year. No EPC contracting state imposes a payment obligation on the filing date itself; the first renewal fee falls due at the earliest in the second, and usually in the third to fifth year of protection. The risk of confusion is not merely linguistic: writing “filing date” instead of “anniversary of the filing date” into a docketing instruction produces miscalculations as soon as the entry is processed automatically.
Overview: renewal fee due dates in the 39 EPC contracting states
| Code | State | Renewal fee due date |
|---|---|---|
| AL | Albania | Last day of the month of filing |
| AT | Austria | Last day of the month of filing |
| BE | Belgium | Last day of the month of filing |
| BG | Bulgaria | Anniversary of the filing date |
| CH | Switzerland | Last day of the month of filing |
| CY | Cyprus | Before expiry of the current year of protection = day before the anniversary; three-month payment window (Rule 41(1)(a) Patent Regs 1998) |
| CZ | Czech Republic | Anniversary of the filing date |
| DE | Germany | Last day of the month of filing (§ 3(2) PatKostG) |
| DK | Denmark | Last day of the month of filing |
| EE | Estonia | Last day of the month of filing |
| ES | Spain | Last day of the month of filing |
| FI | Finland | Last day of the month of filing |
| FR | France | Last day of the month of filing (Art. R613-46 CPI) |
| GB | United Kingdom | Last day of the month of filing |
| GR | Greece | Last day of the month of filing |
| HR | Croatia | Anniversary of the filing date |
| HU | Hungary | Anniversary of the filing date |
| IE | Ireland | Last day of the month of filing |
| IS | Iceland | Last day of the month of filing |
| IT | Italy | Last day of the month of filing |
| LI | Liechtenstein | Last day of the month of filing (common territory with CH) |
| LT | Lithuania | Different scheme: final two months of the current year of protection — check separately |
| LU | Luxembourg | Last day of the month of filing |
| LV | Latvia | Last day of the month of filing |
| MC | Monaco | Last day of the month of filing |
| ME | Montenegro | Anniversary of the filing date (Art. 81(2) Law on Patents) |
| MK | North Macedonia | Anniversary of the filing date |
| MT | Malta | Last day of the month of filing |
| NL | Netherlands | Last day of the month of filing |
| NO | Norway | Last day of the month of filing |
| PL | Poland | Anniversary of the filing date |
| PT | Portugal | Anniversary of the filing date |
| RO | Romania | Anniversary of the filing date |
| RS | Serbia | Anniversary of the filing date |
| SE | Sweden | Last day of the month of filing |
| SI | Slovenia | Anniversary of the filing date |
| SK | Slovakia | Anniversary of the filing date |
| SM | San Marino | Last day of the month of filing |
| TR | Türkiye | Anniversary of the filing date |
The practical consequence: work to the earlier date
One simple and robust working rule follows from this split — and it is the rule the CMS patent formalities guide for Europe recommends as well: after grant, docket to the anniversary of the filing date throughout, not to the end of the month. In the Group 1 states this forgoes an average of a little over two weeks — a price that does not begin to weigh against the risk of missing a due date in Group 2.
The single exception to this rule of thumb is Cyprus, where the preceding day already governs. Anyone with Cyprus in the portfolio must docket that deadline separately.
The special case: grant shortly after the anniversary
A distinct source of error arises where the mention of grant is published shortly after the anniversary of the filing date. In that constellation the first national renewal fee falls due in many states two months from the date of grant — potentially before the three-month validation period expires. Some states allow additional time for payment; by no means all do. In practice this means: if grant falls into that window, country selection for validation should be brought forward so that the first renewal fee does not slip into a surcharge-bearing grace period.
The second question: where must a national representative be appointed?
This question is often asked in the same breath as the due date question, but it operates on a different level and needs to be separated cleanly into three stages.
Stage 1 — proceedings before the EPO
Under Art. 133(2) EPC, natural and legal persons having neither their residence nor their principal place of business in an EPC contracting state must be represented by a professional representative (Art. 134 EPC) in all proceedings before the EPO, with the single exception of filing the European patent application. Legal persons having their seat in a contracting state may act through an employee under Art. 133(3) EPC. For parties established within the EPC territory there is therefore no compulsory representation before the EPO.
Stage 2 — validation and national proceedings
On grant, national procedural law takes over. The relevant connecting factor shifts: what matters is no longer establishment within the EPC territory, but as a rule establishment in the particular state or within the EEA.
For Germany this is governed by § 25 PatG: a person having neither residence, seat nor establishment in Germany may take part in proceedings before the DPMA and the Federal Patent Court, and may assert rights under the patent, only if they have appointed a lawyer (Rechtsanwalt) or patent attorney (Patentanwalt) as domestic representative. That representative is at the same time authorised to act in civil litigation concerning the patent. Parties established in Germany are under no such obligation.
A de facto obligation to instruct a local representative additionally exists wherever validation itself can only be effected through an admitted national representative. This applies in particular to the states requiring a full translation of the specification: Austria (unless granted in German), Bulgaria, Cyprus, the Czech Republic, Estonia, Greece, Italy, Poland, Portugal, Romania, San Marino, Serbia, Slovakia, Spain and Türkiye. In these states instructing a local representative is unavoidable in any event, irrespective of whether national law formally requires it. A second group requires translation of the claims only (including Albania, Croatia, Denmark, Finland, Hungary, Iceland, Latvia, Lithuania, Montenegro, the Netherlands, North Macedonia, Norway, Slovenia and Sweden); there too, filing through a local representative is the norm.
Art. 4 of the Montenegrin Law on Patents illustrates how finely national law can draw these lines. Foreign persons with no seat or residence in Montenegro must in principle be represented by a registered representative or a Montenegrin attorney (para. 1). Expressly permitted without a representative, however, are filing the application, submitting priority documents, paying fees, and receiving the associated communications (para. 2) — provided an address for the receipt of documents in Montenegro is supplied (para. 3). If neither is provided, the office issues an invitation to remedy within three months and otherwise rejects the submission (paras. 4 and 5). Para. 6 adds that the maintenance fee may be paid by any person in the name of the proprietor. Paying the renewal fee in Montenegro therefore requires no representative — but it does require an address for service.
Stage 3 — address for service
Even in those states where the European patent takes effect without translation and without any formal step — Belgium, France, Germany, Ireland, Luxembourg, Malta, Monaco, Switzerland/Liechtenstein and the United Kingdom — appointing a local address for service is advisable. Without one, communications from the national office may well not reach the proprietor, and that includes the reminder about an outstanding renewal fee or service of a revocation action. For Malta an address for service is effectively indispensable for proprietors from outside the EU; Switzerland and Liechtenstein require proof of an address in one of the two states.
Why this distinction matters: compulsory representation is not a mere formality but a liability issue. Where the domestic representative is missing, the proprietor cannot assert rights under the patent pursuant to § 25 PatG — the patent exists but is temporarily unenforceable. And where the address for service is missing, the national office’s fee reminder goes nowhere: the six-month period runs out without the proprietor ever learning of it.
Takeaways for practice
- Before grant, Rule 51(1) EPC applies uniformly — due on the last day of the month of filing.
- After grant that uniformity fragments. 24 contracting states stay with the end of the month, 13 work to the anniversary, and Cyprus to the day before it.
- The safe working rule is to docket to the anniversary of the filing date throughout after grant, and separately to the preceding day for Cyprus.
- “Due on the filing date” has no place in a docketing instruction. What is meant is the anniversary of the filing date; the confusion generates systematic errors once entries are processed automatically.
- Compulsory representation is a three-stage question: Art. 133(2) EPC for EPO proceedings, national law after validation (in Germany § 25 PatG), and an address for service even in states with no validation formalities.
