If you are working out how to patent an idea internationally, the first thing to know is that there is no single worldwide patent: a UK patent, in the words of the UK Intellectual Property Office, "has no influence elsewhere", and every other country grants its own. What does exist is a single international application under the Patent Cooperation Treaty, which now has 159 contracting states and lets an applicant hold its position in all of them for up to 30 or 31 months from the first filing before choosing where to spend real money. This guide sets out the eight steps of that process, what each stage costs at 2026 fee levels, the national phase deadlines that catch applicants out, and the points at which a patent attorney should take over.
How to Patent an Idea Internationally: PCT Steps, Fees and Deadlines
By The Corporate INTL Newsroom · 23 October 2026
Is there such a thing as an international patent?
No: patents are territorial, so protection abroad always ends in a set of national or regional patents, each granted and enforced under local law. The Patent Cooperation Treaty (PCT) does not change that. It is a filing and search system run by the World Intellectual Property Organization (WIPO) under which one international application has effect in every contracting state, while the decision to grant remains with the national or regional patent offices in what is called the "national phase".
That distinction matters commercially. A PCT filing buys time and a common search report; it does not stop a competitor copying your product in any country until a patent is granted there. It also means that, once the international phase ends, the cost of the project multiplies by the number of countries you choose, because each office charges its own fees, may require a translation and usually requires a local representative.
Businesses that already protect their brands abroad will recognise the pattern from trade marks, where the Madrid system plays a similar role; our guide on how to register a trademark internationally covers that side. The difference is that a patent application cannot be refiled later once the invention is public, so the order and timing of the patent steps below is far less forgiving.
Can you patent an idea? What has to be true first
You cannot patent a bare idea; you can patent an invention, which means a concrete product, process or method that meets three tests. According to the UK Intellectual Property Office's guidance on patenting your invention, the invention must be:
- New. It must not have been made publicly available anywhere in the world before the filing date.
- Inventive. It cannot be an obvious change to something that already exists.
- Capable of being made or used. It must be something that can be made and used, a technical process, or a method of doing something.
The same guidance lists what cannot be patented in the UK: literary, dramatic, musical or artistic works; a way of doing business, playing a game or thinking; a method of medical treatment or diagnosis; a discovery, scientific theory or mathematical method; the way information is presented; and software without a technical purpose. Other countries draw these lines differently, which is one reason a search and an attorney's opinion are worth having before money is committed abroad. The boundary between protectable technical contributions and unprotectable ideas is also being tested in AI cases, as the Third Circuit's ruling on AI training and fair use shows from the copyright side.
The practical rule that follows from the novelty test is simple: keep the invention confidential until a first application is on file. A pitch deck, a product launch, a conference talk or a crowdfunding page can destroy novelty in every country at once. Where a disclosure to investors or manufacturers is unavoidable, it should be made under a written non-disclosure agreement.
The three routes: national, regional and PCT
There are three ways to protect a patent abroad, and most international strategies combine them. The UK Intellectual Property Office's guidance on protecting your patent abroad describes them as follows:
- National applications. You apply directly to the patent office of each country, claiming priority from your first filing. This suits protection in only a few countries.
- Regional applications. A single European patent application at the European Patent Office (EPO) can cover more than 30 European countries, including the UK; once granted, it becomes separate patents in the countries you choose.
- A PCT international application. One application can seek protection in more than 150 countries, filed with WIPO directly or through a national or regional office acting as receiving office.
The national route is often called the Paris Convention route, because the right to claim the earlier filing date abroad comes from the Paris Convention's 12-month priority period. The PCT route uses the same priority right but defers the national filings by a further 18 or 19 months.
| Factor | Direct national filings (Paris Convention) | European patent (EPO) | PCT international application |
|---|---|---|---|
| Deadline to file abroad | 12 months from first filing | 12 months from first filing, or at the end of the PCT | 12 months from first filing |
| Decision on countries | At 12 months | At validation after grant | At 30 or 31 months from priority |
| Upfront cost | High: fees, translations and local attorneys in every country at once | Medium: one set of EPO fees until grant | Medium: one set of international fees |
| Search before major spend | No common search | EPO search | International search report and written opinion |
| Best for | Two or three known markets | Several European markets | Uncertain or wide markets, fundraising businesses |
WIPO's own summary of the advantages is that the PCT postpones the major costs associated with seeking multinational patent protection and provides a strong basis for patenting decisions. For a start-up, those extra months are often the period in which it raises money, tests the market or finds a licensee, so the choice of route is as much a finance question as a legal one.
How to patent an idea internationally in eight steps
The short answer is: file a first application, file a PCT application within 12 months, use the international search to decide whether the invention is worth pursuing, then enter the national phase in your chosen countries by month 30 or 31. In more detail, the steps are as follows.
Step 1: Check patentability and keep the invention secret
Before drafting, confirm that the invention passes the novelty and inventive step tests, ideally with a prior art search, and that nothing has been published. Agree who owns the invention: if it was made by employees, contractors or a co-developer, the chain of title should be documented, and if a group plans to hold its intellectual property in a particular entity, that choice interacts with the decision between a branch or subsidiary abroad.
Step 2: Make a first filing to secure a priority date
Most applicants file first in their home office. The UK office points out that a lower-cost start is a UK application, for which the application fee is £75 if e-filed and a search request costs £200 if e-filed, which can then be used as the priority claim for an international filing. The date of this filing is month 0 of everything that follows.
Step 3: File the PCT application within 12 months
The international application must be filed within 12 months of the first filing to claim its priority. The UK receiving office advises filing no later than 11 months from the priority date to allow for problems. At least one applicant must be a national or resident of the UK, the Isle of Man, Guernsey or Gibraltar to use the UK office, and the application must include a request form, description, at least one claim, an abstract and any drawings referred to; the UK guidance warns that a filing date cannot be given if no claims are present. Transmittal, search and international fees are due within one month of filing.
Step 4: Receive the international search report and written opinion
An International Searching Authority identifies the most relevant prior art and issues a written opinion on patentability. For applications filed at the UK office the search is carried out by the EPO at The Hague, and the report is expected within about 16 months of the earliest priority date. Within two months of the report the claims can be amended. A supplementary international search by a second authority is optional and can pick up documents in other languages.
Step 5: International publication at 18 months
WIPO publishes the application shortly after the expiration of 18 months from the priority date. If the search shows the invention is not new and you want to keep it confidential, a withdrawal must reach the International Bureau no later than 17 months and two weeks from the priority date to prevent publication.
Step 6: Decide whether to request international preliminary examination
Preliminary examination under Chapter II of the PCT is optional. It lets the applicant amend the application and argue with the examiner before the national phase, and produces a further report. The demand must be filed within three months of the search report or 22 months from priority, whichever expires later.
Step 7: Choose countries and budget for the national phase
Between months 18 and 28, the applicant decides which markets justify the spend: where it sells, manufactures or licenses, and where competitors operate. Translations, local attorneys and national fees should be costed country by country.
Step 8: Enter the national or regional phase by month 30 or 31
The applicant files the required forms, fees and translations with each chosen office before its deadline. From then on, each office examines the application under its own law, and each granted patent must be renewed every year to stay in force.
PCT timeline at a glance
The PCT timeline runs from the priority date, not the date of the international application. The month markers below are taken from the UK Intellectual Property Office's guidance for PCT applicants and WIPO's FAQs.
| Month from priority | Event | What the applicant does |
|---|---|---|
| 0 | First (priority) filing | File nationally; keep the invention confidential |
| 11 | Recommended PCT filing point (UK office) | File the international application and pay fees within one month |
| 12 | Priority period ends | Last day to claim priority without restoration |
| About 16 | International search report and written opinion; priority document deadline | Review prior art; consider amending claims within two months |
| 17 and two weeks | Last day to withdraw and prevent publication | Withdraw only if confidentiality matters more than protection |
| 18 | International publication | Application becomes public worldwide |
| 22 (or three months after the search report, if later) | Chapter II demand deadline | Request preliminary examination if useful |
| 30 or 31 | National and regional phase entry | File forms, fees and translations in chosen countries |
How much does an international patent cost?
The international phase of a PCT application filed in the UK costs about £3,000 in official fees, but the full cost of protection abroad depends almost entirely on how many countries are entered and is not knowable at the outset. WIPO's FAQs put the international filing fee at 1,330 Swiss francs, with search fees of approximately 150 to 2,000 Swiss francs depending on the searching authority, plus a small transmittal fee. In sterling and euro terms, the UK and European offices publish these 2026 figures:
| Fee (international phase) | UK IPO as receiving office (from 1 April 2026) | EPO as receiving office (from 1 April 2026) |
|---|---|---|
| Transmittal fee | £100 | €160 |
| International search fee (EPO as searching authority) | £1,632 | €1,885 |
| International filing fee, first 30 sheets | £1,242 | €1,428 |
| Each sheet over 30 | £14 | Not stated on the EPO summary |
| Preliminary examination fee (EPO) | Paid to the EPO | €2,010 |
| Restoration of priority | £200 | Not stated on the EPO summary |
The UK office's worked example is that an application of 30 sheets or fewer, with all states designated, costs £2,974 for the initial filing, and it stresses that PCT fees must be paid in full, that late payment attracts a surcharge and that no reminders are issued. The EPO's fees for international applications also show what follows at the regional phase: a filing fee of €135 online, a designation fee of €720, and search and examination fees on the same scale as a direct European application.
Several reductions exist. Electronic filers receive fee reductions, and WIPO grants 90% reductions of certain fees, including the international filing fee, to natural persons who meet its eligibility criteria aimed at applicants from developing countries, and to anyone who is a national of and resides in a least developed country. For context on the domestic baseline, the UK office says a UK patent costs at least £405 in official fees if the process is completed, and that professional help can cost several thousand pounds.
The largest costs come later: national and regional fees, translations, local attorneys during examination, and annual renewal fees in every country for up to 20 years. That is why the PCT's main financial value is the option it creates: an applicant with a weak search report can stop at month 18 having spent a fraction of what direct filings in ten countries would have cost.
PCT national phase deadlines by country
The standard deadline for entering the national phase is 30 months from the priority date, but several major offices allow 31 months and a few have special rules. WIPO maintains the official table of time limits for entering the national and regional phase; a selection of commonly chosen offices is below.
| Office | Deadline from priority (Chapter I / Chapter II) | Notes |
|---|---|---|
| European Patent Office | 31 / 31 months | One regional phase for the European patent route |
| United Kingdom | 31 / 31 months | Can also be reached through the European route |
| Australia, Republic of Korea, India | 31 / 31 months | Standard period |
| United States, Japan, Brazil | 30 / 30 months | Standard period |
| China | 30 / 30 months | 32 months if an additional late-entry fee is paid |
| Canada | 30 / 30 months | Reinstatement possible up to 12 months after the deadline |
| Singapore | 30 / 30 months | Extendable by up to 18 months with a fee |
| Bosnia and Herzegovina | 34 / 34 months | Longest standard period listed |
| Luxembourg | 20 / 30 months | Does not yet apply the 30-month Chapter I limit |
Because most deadlines fall at 30 months, many businesses diarise month 30 for every country and treat the 31-month offices as a margin rather than a plan. Where China, Japan, Korea or India are in scope, translations need to be commissioned well before the deadline, and local counsel instructed early; the Find an Expert directory lists intellectual property advisers in China and India, among other jurisdictions.
European patents and the Unitary Patent after the PCT
For European markets, most PCT applicants enter the regional phase at the EPO rather than filing in individual European countries, because one examination covers the whole region. After grant, the patent owner can validate the European patent country by country or request a Unitary Patent, which gives uniform protection in the EU states that have ratified the Unified Patent Court Agreement. The EPO says the Unitary Patent currently takes effect in 18 EU member states, including Germany, France, Italy and the Netherlands, with a single renewal fee paid in euros.
The choice is not only administrative. A Unitary Patent can be revoked or enforced for all participating states in a single action before the Unified Patent Court, which raises both the reward and the risk; our explainer on UPC patent litigation covers how that court works in practice. Owners with major manufacturing or sales in Germany, France or Italy should weigh that risk before deciding. The UK, Spain and Poland, among others, are outside the Unitary Patent and still require national validation of a European patent.
Rules UK residents must check before filing abroad
A UK resident must not file certain patent applications outside the UK without permission. Under section 23 of the Patents Act 1977, the restriction applies where the application contains information relating to military technology, or information whose publication might be prejudicial to national security or to the safety of the public. In those cases, the applicant needs written authority from the comptroller of the Intellectual Property Office, unless a UK application for the same invention was filed at least six weeks earlier and no secrecy directions are in force.
Breaching the section is a criminal offence where the person knew of, or was reckless as to, the contravention. In practice, the simplest way to stay within the section is to file in the UK first and wait at least six weeks before filing abroad. Inventions in defence, aerospace, encryption, energy or dual-use technology should be checked with a UK intellectual property adviser before anything is filed overseas. Where inventors live in more than one country, each country's own rules on filing abroad need to be checked as well.
Common mistakes that cost inventors their rights
Most lost international patent rights come from timing errors rather than weak inventions. The UK office's guidance for PCT applicants and WIPO's FAQs point to the same recurring problems:
- Disclosing before filing. Public use, sale or publication anywhere can destroy novelty in every country.
- Missing the 12-month priority deadline. The UK office says that if the PCT application is filed between 12 and 14 months from the earliest application, restoration of priority can be requested with evidence that the failure was unintentional, for a £200 fee; after that, priority is lost.
- Relying on reminders. The UK guidance states plainly that reminders are not issued at any stage of the PCT process.
- Adding technical content after filing. New matter generally cannot be added, so the first draft must describe every embodiment worth protecting.
- Underbudgeting the national phase. Translations and local attorney fees often exceed the international phase cost several times over.
- Missing the 30-month deadline. Some offices allow late entry or reinstatement, but many do not, and the remedy is never guaranteed.
- Ignoring ownership. An application filed in the wrong name, or without assignments from inventors, can be challenged later, which matters in high-value disputes such as Apple's $5.7bn Taptic Engine patent loss.
Who files most international patent applications
The PCT is used most heavily by applicants in East Asia, the United States and Europe. WIPO's PCT Yearly Review 2026 records about 275,900 PCT applications in 2025, up 0.7% on 2024. Applicants in China filed 73,718, followed by the United States (52,617), Japan (47,922), the Republic of Korea (25,016) and Germany (16,441); applicants in the UK filed 5,809. The same review records 645,100 PCT national phase entries in 2024, the latest year available, and estimates that PCT national phase entries made up 53.3% of all non-resident patent filings worldwide.
For a business, the useful reading of those numbers is that competitors in technology sectors are likely to be using the PCT already, and that their published applications, available from month 18, are a source of competitive intelligence. Once granted, patents in standards-heavy sectors can also become the subject of global licensing disputes, as the Optis FRAND case shows.
When to bring in a patent attorney
The UK office's own advice to PCT applicants is direct: "You are strongly advised to seek the help of a chartered patent attorney". Specialist help adds most value at four points: drafting the first application, because its content fixes what can ever be claimed; responding to the international search report; choosing countries before month 30; and coordinating local attorneys through national examination.
Before a first meeting, gather a description of the invention and how it differs from what exists, any prior art you know of, dates and details of any disclosures, the names and employment status of every inventor, your target markets and your budget. The Corporate INTL Find an Expert directory lists intellectual property advisers worldwide, including specialists in the United States, alongside life sciences and pharmaceutical lawyers for medical and biotech inventions and licensing specialists for owners planning to license rather than manufacture. Each expert page carries a "Looking for legal or business advice?" form, which readers can use to send an enquiry and be matched with a suitable adviser. For more on patent disputes and policy, see our intellectual property coverage.
Frequently asked questions
How do you patent an idea internationally?
File a first patent application at home, then file a PCT international application within 12 months claiming its priority. Use the international search report to judge patentability, then enter the national or regional phase in each chosen country by month 30 or 31. Each country examines and grants its own patent.
Is there a worldwide patent?
No. Patents are territorial, and the UK Intellectual Property Office says a UK patent has no influence elsewhere. The PCT lets one application take effect in 159 contracting states during the international phase, but protection only comes from national or regional patents granted after national phase entry.
Can you get a patent on just an idea?
No. A patent protects an invention: a product, process or method that is new, inventive and capable of being made or used. Ideas, discoveries, business methods, mathematical methods and non-technical software are excluded in the UK. The idea must be developed into a concrete technical solution and described in enough detail to be carried out.
How much does it cost to get an international patent?
The international phase of a PCT filed in the UK costs £2,974 in official fees for an application of up to 30 sheets, at rates from 1 April 2026. National phase fees, translations, attorney fees and annual renewals in each country come on top and usually make up most of the total cost.
What is the difference between the Paris Convention and the PCT?
Under the Paris Convention route you file directly in each country within 12 months of your first filing. The PCT route uses the same 12-month priority but lets you file one international application and defer national filings until month 30 or 31, with an international search in between.
Which countries have a 31-month PCT deadline?
WIPO's time limits table lists 31 months for the European Patent Office, the United Kingdom, Australia, the Republic of Korea, India and the Eurasian Patent Organization, among others. The United States, Japan, Brazil and China apply 30 months, although China allows 32 months with an extra fee.
When is a PCT application published?
WIPO publishes the international application shortly after 18 months from the priority date. To prevent publication, a withdrawal must reach the International Bureau no later than 17 months and two weeks from the priority date, according to the UK Intellectual Property Office's PCT guidance.
What happens if I miss the 12-month priority deadline?
If a PCT application is filed between 12 and 14 months from the earliest application, the UK receiving office can restore priority on evidence that the delay was unintentional, for a £200 fee. After 14 months the priority claim is lost, and any disclosure in the meantime may destroy novelty.
Do UK residents need permission to file a patent abroad?
Only for applications containing information about military technology, or information that might prejudice national security or public safety. Under section 23 of the Patents Act 1977, these need written permission unless a UK application was filed at least six weeks earlier and no secrecy directions apply.
Sources
- WIPO: Protecting your Inventions Abroad, Frequently Asked Questions About the PCT (updated August 2026)
- WIPO: Time limits for entering the national and regional phase under the PCT
- UK Intellectual Property Office: Protecting your patent abroad (updated 4 June 2026)
- UK Intellectual Property Office: Patent Cooperation Treaty (PCT) for private applicants (updated 1 April 2026)
- European Patent Office: Fees for international applications (applicable as of 1 April 2026)
- Patents Act 1977, section 23: Restrictions on applications abroad by United Kingdom residents
- WIPO: PCT Yearly Review 2026, Executive Summary
- European Patent Office: Unitary Patent
- UK Intellectual Property Office: Patenting your invention
About this article
This guide was researched and written by The Corporate INTL Newsroom, which covers cross-border legal, regulatory and business developments for lawyers, professional advisers and financiers in over 150 jurisdictions. It has been checked against WIPO's PCT guidance and statistics, the UK Intellectual Property Office's published guidance and fee schedules, the European Patent Office's fee tables and the Patents Act 1977. Fees and deadlines change and differ between offices, so confirm current figures with the relevant office before filing. This article is general information, not legal advice; for advice on a specific invention, consult a qualified patent attorney. Last reviewed 23 October 2026. For more analysis like this, visit the Corporate INTL newsroom or subscribe to Corporate INTL.
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