PCT International Applications: Procedure, Timeline, and Fees

Protecting one invention in multiple countries comes down to either separate national filings or one PCT international application. PCT is not a single "world patent" — it's a procedure that buys you time and produces a search report. From the priority date, you have 30 months (or 31 in some offices) before you must commit to specific countries, which is enough room to validate markets, line up funding, or assess the international search results. This article walks through the procedure, deadlines, and fees from KIPO and WIPO sources.

Five stages of a PCT life cycle

PCT splits into the international phase and the national phase, with five steps in between.

1. International filing: submit the PCT request, specification, claims, and drawings to a Receiving Office (e.g., KIPO) — one filing designates all 156+ PCT contracting states
2. International search: an International Searching Authority (ISA) issues an International Search Report (ISR) and a Written Opinion
3. International publication: WIPO publishes the application 18 months from the priority date — the application becomes public
4. International preliminary examination (optional): the applicant may demand it within 22 months from priority (or 3 months from ISR). Result: an International Preliminary Report on Patentability (IPRP)
5. National-phase entry: by the 30-month deadline (most offices) or 31 months (EPO and some others), file translations and the national paperwork in each chosen country

International search — ISR + Written Opinion

The ISA evaluates novelty, inventive step, and industrial applicability and issues the ISR plus a Written Opinion. National examiners reference these documents during national-phase examination. A favorable ISR makes downstream grant easier; a negative one prompts strategic narrowing of countries or claim adjustments before entry.

International preliminary exam — optional but useful

Demanding international preliminary examination is optional. If demanded, the applicant amends/argues against the Written Opinion, producing the IPRP. A favorable IPRP often speeds national-phase examination and can support PPH (Patent Prosecution Highway) leverage in some offices. If not demanded, the ISR + Written Opinion stand in for the IPRP.

National-phase entry — 30 / 31 months

The 30-month (or 31-month for EPO) window from the priority date is the actual point of PCT. By the deadline, you must file translations (where required) and the national paperwork. Korea is 30 months; EPO is 31 months. Confirm exact deadlines for each office on the WIPO time-limits table.

Fees — PCT via KIPO as Receiving Office

Per KIPO's PCT fee guide, three line items make up the international-stage fees: transmittal fee, international filing fee, and search fee. Exchange rates move so verify the current numbers before filing.

PCT vs Paris Convention direct filing

Frequently asked questions

Does a PCT filing become an "international patent"?

No. PCT filing secures priority for national-phase entry — it isn't a single international patent. Actual patent rights still arise country by country during national-phase examination. The same PCT can lead to a Korean patent and a US rejection. Treat PCT as "time + a search report," not "a patent."

Can I file a PCT application in Korean?

Yes. KIPO acts as Receiving Office, ISA, and IPEA for Korean-language filings. National-phase entries outside Korea will require translations into the receiving country's official language — English is the most common target.

Do I have to commit to all countries by the 30-month deadline?

The deadline is per country. You enter the countries you want by their respective 30-month (or 31-month) deadlines. There's no obligation to enter every PCT contracting state — and every missed deadline is effectively a lost national right, which is hard or impossible to restore.