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.

The priority number is made up of a country code (two letters), the year of filing (four digits) and a serial number (variable, maximum seven digits). A serial number having less than seven digits can be rounded up to seven digits by adding zeros (e.g. GB19950008026).

Alternatively, the zeros can be omitted entirely (e.g. GB19958026).

For some documents in Espacenet there may be 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 for 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 numeric 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 search criteria (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.

For more information on patent searching, see the following pages:

• Default operator
• Boolean operators
• Limitations
• Country codes
• Number formats