What Is a PCT Patent? Filing, Search, and National Phase

A PCT patent application is a single international filing under the Patent Cooperation Treaty that preserves your right to seek patent protection in up to 158 countries without immediately paying to file in each one. It doesn’t produce a patent by itself. What it buys you is time — up to 30 months from your earliest priority date — to decide where you actually want patent rights, while an international search evaluates whether your invention is likely patentable.¹

What the PCT Actually Gives You

The Patent Cooperation Treaty is a 1970 agreement administered by the World Intellectual Property Organization (WIPO), with 158 contracting states today.² You file one application, in one language, with one patent office, and that filing has the legal effect of a separate national application in every PCT member country.

The point most first-time applicants miss: a PCT application never matures into a granted patent on its own. Every country’s patent office still decides independently, under its own laws, whether to grant you a patent. The PCT is a structured runway toward those decisions, not a substitute for them.

Some countries sit outside the system, including Argentina, Venezuela, Pakistan, Bangladesh, and Taiwan. If you need protection there, you have to file directly with that country’s patent office.

When the PCT Route Makes Sense

The PCT isn’t your only option. Under the Paris Convention, you can file separate applications directly in each country you want protection in, claiming priority from your original home-country filing within 12 months. The Paris Convention doesn’t create any centralized application; it just secures your original filing date for those later national filings.³

If you only need protection in two or three countries and you already know which ones, filing directly under the Paris Convention is often faster and cheaper. You skip the PCT international fees and go straight to national prosecution. But if you’re targeting five or more countries, or you don’t yet know which markets will matter, the PCT almost always wins. It pushes the heavy costs of translation, national fees, and local patent agents out by roughly 18 additional months beyond what the Paris Convention gives you, which is time to test markets, raise money, or find licensing partners.⁴

How to File a PCT Application

A PCT application has five basic components: a request form, a description of the invention, one or more claims defining the scope of protection, an abstract, and any drawings needed to understand the invention. These are assembled on the standardized PCT Request Form (PCT/RO/101).⁵

You can file with your national patent office as the “receiving office,” with a regional patent office, or directly with WIPO’s International Bureau. A U.S. applicant would typically file with the USPTO. Most applicants now use WIPO’s ePCT system, which runs automated checks against PCT regulations and provides secure access to the application throughout the process.⁶

Claiming Priority From an Earlier Filing

Most PCT applicants have already filed something at home. A U.S. provisional application qualifies as a priority basis. To claim its priority date, you must file the PCT application within 12 months of that earlier filing. Miss that window and your priority is at risk, though a two-month grace period exists: your priority claim won’t automatically be treated as void if the PCT filing lands within two months after the 12-month deadline.³

Unity of Invention

A PCT application must relate to a single invention, or to a group of inventions linked by one inventive concept. If your claims cover unrelated inventions, the searching authority will flag a “lack of unity” and search only the first invention unless you pay additional search fees for the others.⁷ The test is whether the claimed inventions share “special technical features” that together represent a contribution over the prior art. Applicants get hit with unexpected fees here often, so keep claims tightly related.

Foreign Filing License for U.S. Inventors

If the invention was made in the United States, you generally need a foreign filing license before the USPTO can forward your application to any foreign office or international authority. Filing with the USPTO as your receiving office handles this automatically; the filing is treated as including a license request. If you file directly with a foreign receiving office, you have to petition separately for the license first.⁸

A license isn’t required if the invention wasn’t made in the U.S., or if a U.S. national application on the same invention was filed at least six months earlier and isn’t under a secrecy order.⁸ Violating this requirement can jeopardize your U.S. patent rights entirely. Don’t treat it as a formality.

The International Search and Written Opinion

After you file, an International Searching Authority (ISA) searches earlier patents, published applications, and technical literature to assess whether your invention appears to be new. The ISA is a designated patent office; if you file through the USPTO, the USPTO typically serves as the ISA. The search report is due within three months of the ISA receiving your application or nine months from the priority date, whichever is later.⁹

The ISA produces two documents: the International Search Report (ISR), listing relevant prior art, and a Written Opinion on whether your claims appear novel, non-obvious, and industrially applicable.¹⁰ Neither is binding on any national office, but both are useful. A negative written opinion tells you early that your claims need work, which can save thousands of dollars in national filings that would fail anyway.

Publication at 18 Months

WIPO publishes your international application, together with the international search report, shortly after 18 months from the priority date. Until publication, no third party can access your application unless you authorize it.¹¹ After publication, anyone can read the application and the search report. Competitors get to evaluate your claims, and the published document may itself count as prior art against later filings by others.

Optional Preliminary Examination

If the written opinion raises patentability concerns, you can request an International Preliminary Examination before entering the national phase. This is often called Chapter II. The examining authority (IPEA) reviews your claims — including any amendments you’ve made in response to the initial written opinion — and issues a second non-binding assessment.¹⁰

The deadline for filing a demand is 22 months from the priority date or three months from the date the written opinion was issued, whichever is later. Chapter II adds cost, and in practice relatively few applicants use it today. Many prefer to amend claims directly during national phase prosecution instead.

Entering the National Phase

This is where a single international application splits into actual patent prosecution in each country you’ve chosen. You must enter the national phase within 30 months of your earliest priority date in most countries, though a few jurisdictions allow 31 months.¹ Each office runs its own process, but three requirements are nearly universal:

Translation into the local language of each office where you file.¹²
National filing and examination fees. The USPTO’s basic national fee for entering the U.S. national stage is $350, reduced to $140 for small entities and $70 for micro entities.¹²
Appointment of a registered patent attorney or agent in most jurisdictions to handle prosecution locally.¹²

The national phase is by far the most expensive stage. Translation runs $0.05 to $0.25 per word for technical patent documents, and a 30-page application translated into five languages adds up quickly. Professional attorney fees for handling national phase entry typically fall between $500 and $3,000 per country. Multiply that across your target list, and the value of the PCT’s 30-month delay becomes obvious.

If You Miss the Deadline

Miss the national phase deadline and your application is generally treated as abandoned in the countries where you didn’t file. Some offices allow restoration of rights, but the standards vary. The U.S. and U.K. apply an “unintentional” standard — you show the delay wasn’t deliberate. Countries like Denmark and Spain apply a stricter “due care” standard, requiring proof that you took reasonable steps to meet the deadline.¹³ Restoration is discretionary, involves added fees, and is never guaranteed. Treat the 30-month deadline as hard.

What It Costs at the International Stage

Fees during the international phase come from three places: WIPO, the receiving office, and the searching authority. Figures below are effective March 1, 2026.

International filing fee (WIPO): $1,667 (CHF 1,330). Applications over 30 pages add $19 per extra page. Electronic filing reduces the fee by CHF 100 to 300 depending on format.¹⁴
Transmittal fee (USPTO as receiving office): $285, reduced to $114 for small entities and $57 for micro entities.¹⁵
Search fee (USPTO as ISA): $2,400, reduced to $960 for small entities and $480 for micro entities.¹⁵
Preliminary examination fee (optional Chapter II, USPTO as IPEA where USPTO was not your ISA): $880, reduced to $352 for small entities and $176 for micro entities.¹⁶

For a standard-size application filed through the USPTO with the USPTO as ISA, expect roughly $4,350 in international-phase government fees at the regular rate. A micro entity filing the same application would pay closer to $1,800. WIPO also offers a 90% reduction in the international filing fee for applicants from certain developing countries, which can bring that component under $170.¹⁴

Key Deadlines at a Glance

The PCT process runs on a strict calendar measured from your earliest priority date. Losing track of any deadline can forfeit rights permanently.

12 months: file the PCT application if claiming priority from an earlier national filing.³
Around 16 months: international search report typically completed (ISA has until 3 months after receiving the search copy or 9 months from the priority date, whichever is later).¹⁷
18 months: WIPO publishes the application and search report.¹¹
22 months: deadline to file a Chapter II demand for preliminary examination (or 3 months after the written opinion, whichever is later).
30 months: deadline to enter the national phase in most countries.¹

1
World Intellectual Property Organization (WIPO). Summary of the Patent Cooperation Treaty (PCT) (1970)
2
WIPO. The PCT Now Has 158 Contracting States
3
WIPO. PCT Receiving Office Guidelines – Chapter VII: Priority Claims and Priority Documents
4
WIPO. Patent Cooperation Treaty (PCT) (1970)
5
United States Patent and Trademark Office. 1812 Elements of the International Application
6
WIPO. ePCT – WIPOs Global Patent Gateway for Filing and Managing PCT Applications
7
eCFR. 37 CFR 1.475 – Unity of Invention Before the International Searching Authority, the International Preliminary Examining Authority and During the National Stage
8
United States Patent and Trademark Office. License Request for Foreign Filing Under the PCT
9
United States Patent and Trademark Office. 1844 The International Search Report
10
United States Patent and Trademark Office. 1843 The International Search
11
WIPO. Protecting Your Inventions Abroad: Frequently Asked Questions About the Patent Cooperation Treaty (PCT)
12
WIPO PCT Applicant’s Guide. PCT Applicants Guide United States of America
13
WIPO. Restoration of the Right of Priority
14
WIPO. PCT Fee Tables
15
United States Patent and Trademark Office. PCT Fees in US Dollars
16
United States Patent and Trademark Office. USPTO Fee Schedule – Current
17
United States Patent and Trackmark Office. 1844 The International Search Report