U.S. Filing

0 months: File local application

Generally, patent applicants who wish to protect their invention in more than one country usually first file a national or regional patent application with their national or regional Patent Office.

Foreign filing rights can be preserved by filing a patent application in the applicant's home country or region prior to public disclosure being made.

Patent Cooperation Treaty (“PCT”) Filing Deadline

12 months: File PCT application

An international application under the PCT is generally filed within 12 months after the filing of the first application directed to the same subject matter so that priority may be claimed.

What does it mean to “claim priority” of an earlier patent application? Generally, patent applicants who wish to protect their invention in more than one country usually first file a national or regional patent application with their national or regional patent Office, and within 12 months from the filing date of that first application, they file their international application under the PCT. The effect of claiming the priority of an earlier patent application is that a patent shall not be invalidated by reasons of any acts accomplished in the interval, such as another filing, the publication or sale of the invention.
Source: https://www.wipo.int/pct/en/faqs/faqs.html

International search report & written opinion

16 months: International Search

The International Search Report (“ISR”)and Written Opinion is typically issued a few months after the international filing date. The ISR will provide an idea of what prior art exists and what issues and rejections may arise when the application enters the national/regional phase. Together with the search report, the International Searching Authority (“ISA”) prepares a written opinion on patentability, giving a detailed analysis of the potential patentability of an invention.

International Publication

18 months: International Publication

World Intellectual Property Organization (“WIPO“) publishes the international application as soon as possible after the expiration of 18 months from the earliest filing date, together with the international search report.

PCT international applications are published online on PATENTSCOPE, a fully searchable database. [...]

Supplementary International Search Report

28 months: International Preliminary Examination (optional)

Generally similar in content and appearance to the main international search report, this contains references to patent documents which may affect the patentability of the invention claimed in the international application. It does not repeat documents which have already been cited unless relevant. Occasionally, the supplementary international search report may contain more detailed explanations if no written opinion is established with the supplementary international search report. These additional details are helpful for a full understanding of the references listed.

The National Phase

30/31 months: Beginning the National and Regional Phase

This next step allows entry into individual countries and/or regions. Once the PCT application has entered the national phase, the national and/or regional patent offices begin the process of determining whether they will grant the patent. Any examination which these offices undertake may be made easier by the PCT International Search Report and Written Opinion (ISR) and an international preliminary examination report.