PCT National Phase in Denmark: A 2026 DKPTO Filing Guide

An international patent application buys you time, not protection. A PCT filing keeps your options open across most of the world for a while, but it never matures into an enforceable Danish patent on its own. To turn that option into a real right you have to leave the international system and enter the country — and the PCT national phase in Denmark is where that happens. Miss the deadline and there is rarely a way back. Understand it, and Denmark becomes one of the more applicant-friendly markets in Europe to enter, thanks to an office that will work in English.

How the PCT National Phase in Denmark Works

Your PCT application went through an international phase — an international search, perhaps a preliminary examination, and publication by WIPO. None of that grants a patent anywhere. A PCT application is a placeholder that reserves your filing date in over 150 countries while you decide where protection is actually worth paying for. The clock never stops, though: every national deadline is measured from your original priority date, so the freedom the PCT buys is strictly time-limited.

Entering the PCT national phase in Denmark is the act of converting that reservation into a live Danish application. You choose Denmark, meet the formalities, pay the fees, and from that point the Danish Patent and Trademark Office (DKPTO) treats your file like any other national application heading toward examination and grant.

If you are still mapping your overall route into the country, read this alongside our guide on how to file a patent in Denmark, which compares the national, European and unitary options at a higher level.

The 31-Month Deadline — and Why It’s Effectively Final

Denmark’s national-phase deadline is 31 months from the priority date. If your PCT application claimed no priority, the clock runs 31 months from the international filing date instead. That single date matters more than anything else in this process.

Treat it as a hard wall. The Danish Patents Act allows the deadline to be restored in narrow circumstances — broadly, where entry was missed despite all due care that the situation demanded, and the request is filed within two months of the removal of the cause and no later than twelve months after the missed deadline. That is a strict standard, granted sparingly and never something to plan around. In practice, a blown 31-month deadline usually ends the Danish route for that invention.

The takeaway is unglamorous but decisive: dock the date the moment you file the PCT application, not when the deadline looms. Late entry is one of the most common and most avoidable ways applicants lose a market.

Two Routes In: Direct DKPTO vs the Euro-PCT Route

Denmark gives you two doors, and the 31-month deadline is the same for both. Choosing between them is the real strategic decision:

• Direct national phase at the DKPTO. You enter Denmark directly and end up with a purely Danish national patent, examined and granted by the DKPTO. Clean and cost-effective when Denmark is your only European target.
• The Euro-PCT route. You enter the European regional phase at the EPO instead, and the resulting European patent takes effect in Denmark — either as a classic validated patent or, if you elect it, as a Unitary Patent covering Denmark alongside the other participating states.

The decision rule we use most often: if Denmark is one of several European countries you want, the Euro-PCT route through the EPO is usually more efficient than a handful of separate national filings, and it opens the door to the Unitary Patent. If Denmark stands alone, direct entry at the DKPTO is simpler and cheaper. Our post on validating a European patent in Denmark covers the second route in depth.

Documents, Translations and Language

This is where Denmark is genuinely easier than much of Europe. According to the DKPTO, the office accepts applications in English, so if your PCT application is already in English you can file and prosecute the whole case in English — a real relief for applicants coming from the US, the UK or Asia, and a meaningful saving on the translation bill that so often inflates national-phase budgets elsewhere.

A Danish translation of the claims is required by the time the patent is granted rather than at entry, which spreads the cost and the effort across the prosecution rather than loading it onto the deadline. Confirm the wording of the granted claims carefully, because in Denmark it is the claims that define what you can actually enforce.

Foreign applicants without a domicile in Denmark will normally act through a local representative before the DKPTO, so put that relationship in place early rather than at the deadline.

Fees, Examination and Grant

Entering the national phase means paying the DKPTO’s application fee, after which renewal (annuity) fees fall due to keep the application and, later, the granted patent alive. The exact figures are set by the DKPTO and are modest by European standards, but they compound over a patent’s twenty-year life, so build the annuity schedule into your budget from the start.

Once in, the DKPTO conducts a substantive examination for novelty and inventive step. Because your PCT application already carries an international search report — and often a written opinion or preliminary examination — that earlier work can streamline the Danish prosecution. A favourable international opinion does not bind the DKPTO, but it is a strong head start.

For a broader view of how the international application itself is assembled, see our guide on filing a PCT international patent application.

After Grant: Where You Enforce a Danish Patent

The route you choose at 31 months decides where you litigate later. A purely national Danish patent — the product of direct DKPTO entry — is enforced before the Maritime and Commercial High Court (Sø- og Handelsretten) in Copenhagen, the specialist forum for Danish patent disputes, with appeal to the Supreme Court. The Unified Patent Court has no jurisdiction over a purely national patent.

If you took the Euro-PCT route and the resulting European patent has effect in Denmark, the picture changes: unless you have opted out, that patent falls under the UPC, and Denmark’s forum is its own local division seated in Copenhagen — not a shared regional division. Same city, a very different court and a very different reach, because a single UPC judgment can cover every participating state at once. That is one more reason the direct-versus-Euro-PCT choice deserves real thought at entry, not after grant.

The practical lesson is that national-phase entry is not just a filing formality; it is a litigation decision made years in advance. The forum, the geographic reach of any injunction, and the risk of a single central revocation attack all trace back to the door you chose at 31 months. Decide it deliberately, with enforcement in mind, rather than defaulting to whichever route looks cheapest on the day. Our guide to patent litigation in Denmark unpacks the forum choice in full.

How PerspireIP Can Help

PerspireIP dockets your 31-month deadline, advises whether the direct DKPTO route or the Euro-PCT route fits your strategy, and manages the Danish national phase from entry through grant. Explore our Denmark IP hub and our teams in Copenhagen and Aarhus, then contact us well before the clock runs out.

Frequently Asked Questions