WO (PCT) application number

The European Patent Register provides file inspection for all publicly available EP applications, Euro-PCT applications (entry into the regional phase, Form 1200) and for international applications under the PCT, where the EPO has been designated as one of the following:

  • Receiving Office (PCTRO)
  • International Searching Authority (PCTISA)
  • Supplementary International Searching Authority (SISA)
  • International Preliminary Examination Authority (IPEA) (PCT2)


OJ EPO 2003, 382
OJ 2018, A14
Article 30 PCT

Searching with PCT application numbers

The standard number format for searching for PCT applications in the Register consists of the WIPO code WO followed by the year of filing (four digits), the country code of the country (two characters) and a five-digit serial number, adding up to a fixed length of 13 characters. For example:

  • WO2007IB51010
  • WO2005DE00977
  • WO2001US20091

Not all national offices use this standard format. In such cases, you must transform the number into the standard format to obtain a result. This may mean omitting leading zeros:

  • PCT/IB2008/012345 must be entered as WO2008IB12345
  • PCT/US/1998004141 must be entered as WO1998US04141

In some cases, however, you may need to change the number completely:

  • PCT/IB2007/51010 or IB200751010 must be entered as WO2007IB51010

In the Register, you can search for all types of patent document number (e.g. application, publication and priority number) by entering the search syntax num= in the Smart search screen. If you want to search for a particular type of patent document number, you can use a corresponding field identifier. For example, if you want to search for the application number only, enter your search using the field identifier ap= followed by the number, e.g. ap=WO2007IB51010. In the Advanced search screen, simply enter the numbers as they stand in the corresponding search fields.

Related topics

Advanced search

Smart search field identifiers