International (PCT) Patent Applications: Global Patent Filing under the PCT Agreement

At Patentarea, we help IP firms, inventors and companies file, manage, and enforce international patent applications under the Patent Cooperation Treaty (PCT). Our team ensures precision, strategy, and seamless international coordination.

What Is a PCT Application?

A PCT application does not mean your invention has been filed in multiple countries. Instead, it is a legal tool under the Patent Cooperation Treaty that allows applicants to extend the time available to pursue patent protection in each desired country up to 30 (or 31) months from the priority date. To pursue patent protection in each desired country.

Filing a PCT application enables inventors and companies to:

• Secure an international filing date while maintaining the option to choose the specific countries later (30 or 31 months from the priority date).
• Postpone the cost and complexity of filing in individual national or regional patent offices.
• Receive a preliminary opinion on patentability, aiding strategic decisions, called “Written Opinion”.
• Potentially expedite examination during the national phase, as national patent offices can access the international search report, written opinion, and any amendments or arguments made during the international phase.

Without a PCT application, foreign patent applications must be filed in each country within 12 months from the first filing (according to the Paris Convention). However, if a PCT application is filed within this 12-month period, it defers the deadline for national filings to 30 or 31 months, depending on the country.

In short, a PCT application is not a patent, but a procedural bridge, offering time, insights, and flexibility for global patent protection.

The PCT Application Process

The PCT system offers two options for initiating the process, depending on whether a prior patent application has already been filed. The filing method determines the priority date and deadline for the national phases, but the subsequent stages remain the same.

How Much Does a PCT Application Cost?

The cost of filing a PCT application varies depending on the filing route, the chosen authorities, and the countries selected for national protection. Applicants should be aware that the PCT process involves three main cost stages: International Filing, Optional Chapter II Examination, and National Phase Entries.

For a more detailed breakdown of costs throughout the full patent life cycle, see our dedicated post: Understanding International Patent Costs: From Filing to Grant

International Filing Costs

The initial filing stage includes several fees, and the total amount depends on where and how the PCT application is filed. Costs typically include a filing fee, a search fee determined by the selected International Searching Authority (ISA), and a transmittal fee, charged by the Receiving Office.

On average, international phase costs range between US$ 2,000 and US$ 5,500, depending on page count, language, applicant status (e.g., small entity), and office selection. For example, Using the Korean Intellectual Property Office (KIPO) as the ISA can significantly reduce the search fee. KIPO offers lower rates while maintaining acceptable quality standards, making it a cost-effective option for many applicants.

In contrast, the European Patent Office (EPO) charges one of the highest search fees but is widely recognized for its high examination standards. Choosing the EPO as the ISA may enhance the credibility of the written opinion in the eyes of foreign patent offices and also reduce official fees when entering the national phase in Europe.

These strategic choices can affect both upfront costs and downstream advantages, and should be evaluated based on budget, target jurisdictions, and patent strategy.

Optional Chapter II Examination Costs

If the applicant decides to submit a Chapter II Demand to request further examination, additional fees apply, this ranges between US$ 300 to US$ 2,500 depending on the selected international authority. In addition, attorney or representative fees are usually incurred when preparing and submitting the demand.

This step is not mandatory but can be useful when the applicant wants to amend claims or strengthen the application before entering national phases.

To better understand how Chapter I and Chapter II work within the PCT process, see: PCT: Understanding Chapter I and Chapter II

National Phase Entry Costs

National phase entry is where the bulk of costs occur. These vary widely depending on the countries selected but often include:

• Translation costs, especially in non-English-speaking jurisdictions
• Official fees charged by each national or regional office
• Local attorney or agent fees
• Additional fees for examination, publication, and annuities, depending on the jurisdiction

In most cases, national phase costs are comparable to those incurred when filing directly under the Paris Convention route. The key advantage of the PCT system is that these costs are deferred to 30 or 31 months from the initial filing, allowing more time to plan and allocate resources.

Why Choose the PCT Route?

Filing through the PCT system offers several strategic advantages for inventors, startups, and corporations aiming to protect their innovations globally. More than just a procedural convenience, the PCT framework enhances decision-making, reduces upfront risk, and maximizes the value of each patent opportunity.

We can group the benefits into two primary advantages, each of which brings a range of complementary benefits:

1. Provides Early Insight of your invention through a Written Opinion and Search Report

One of the most valuable features of the PCT system is the preliminary written opinion and international search report issued by the International Searching Authority. These documents provide an early technical assessment of the invention’s novelty, inventive step (non-obviousness), and industrial applicability.

This early feedback enables applicants to:

• Evaluate the patentability of the invention before committing to costly national filings.
• Identify weaknesses in the claims or description and proactively adjust the application.
• Gauge the commercial potential of the invention, especially when the report is favorable.

Example: If the applicant receives a negative written opinion with strong arguments against novelty, such as a prior patent publication that fully anticipates the invention, they may decide to abandon or limit their international filing plans. This can result in significant cost savings, avoiding expenses related to translations, national filing fees, and local attorney services.

In contrast, a positive written opinion confirming novelty, inventive step, and industrial applicability can validate the invention’s strength and encourage broader protection. In this case, applicants may:

• Request accelerated examination in selected jurisdictions through the Patent Prosecution Highway (PPH).
• Use the favorable report to attract investors or licensing partners.
• Prioritize national entries based on market demand and commercial potential.

2. Facilitates Coordination Between International and National Phases

Although each national or regional patent office requires its own examination and compliance with local regulations, the PCT system offers a common procedural foundation that simplifies the transition to national filings.

By filing a single PCT application, the applicant can:

• Use a standardized structure for the description, claims, abstract, and drawings
• Centralize priority data and applicant information, reducing administrative workload. For example, national offices will have direct access to the priority document submitted in the PCT application, which minimizes the need for the applicant to provide separate copies during national phase entry
• Make available international documents such as the search report, written opinion, and any voluntary amendments. These are officially published and accessible to all designated national patent offices for reference during examination.

These elements help national patent offices conduct a more efficient examination. Many offices refer to the international written opinion as a starting point to guide their analysis, and therefore, amendments made by the applicant during the international phase are also taken into account, as they are publicly available and may resolve potential objections in advance. In some jurisdictions, especially those aligned with international standards, relying partially on the international findings can even lead to a reduction in examination time.

Although applicants must still translate and formally file the application in each selected country, the availability of harmonized content and early examination results leads to a more coherent and efficient prosecution process across multiple jurisdictions.