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Priority Number

The priority number is the number of the application in respect of which priority is claimed, i.e. it is the same as the application number of the claimed priority document.


All priority numbers of all countries are standardised to one format, irrespective of the way in which they are printed on the patent documents. There is a fixed length of 13 characters in Espacenet, excluding the kind code. Where necessary, the fixed length is achieved by inserting leading zeros.


For the majority of countries priority numbers in Espacenet are made up of a country code (two letters), the year of filing (four digits), and a serial number (variable, maximum seven digits).


There are twelve countries/organisations which use a different format. These are Australia, Germany, China, Brazil, Ukraine, Gulf Council, Hungary, India, Italy, Mexico, OAPI and WIPO. They use application numbers made up of:


  • a country code (two letters)
  • the year of filing (four digits)
  • "other" information (one or two characters)
  • a serial number (five or six digits)

By way of exception, more recent numbers for Germany and the United States have 14 characters.


Some documents in Espacenet may have an 'X' after the country code of the priority number (e.g. for FR1018027 the "semi-technical" priority number is USX1018027). This is the case in records for which the priority country code and date are known and recorded but the original number is not. In such cases a "semi-technical" priority number is created by taking the numerical part of the (dummy) application number and attaching this number to the known country code and the letter X. Thus a "semi-technical" priority number indicates the country of origin of the invention.


To retrieve all the documents having a particular country code in combination with other entries (dates, etc.), all you have to do is enter the country code (e.g. GB) in the priority number field in combination with a date in the publication date field.


Where a link is available, you can click on the priority number in the Bibliographic data view to go to the document concerned. If there are several documents with the same priority number, the link will take you to a result list.


For more information on Espacenet, see the following pages: