Patent Application and

Patent Timeline

The following timeline should give you an idea of what actions must be done at what time in a US utility patent application. Please note that each application is different, and you should use this timeline as a guide only - check with a patent professional (preferably Brown and Michaels) to determine the specific deadlines which apply to your situation. 

This timeline applies to utility patents filed in 2001 or later, and assumes that you will start with a Provisional Patent Application, then file a Utility Application and PCT and/or foreign applications. In most cases, our clients do not file a Provisional Application at all, and start with a Utility Patent Application. In that case, the Priority Date (PD) will be the same as the Utility Filing Date (UFD). Of course, foreign or PCT patenting is entirely optional. This chart does not apply to Design Patents or Plant Patents, which are subject to other rules. 

Also note that the dates given are the latest possible dates to file - you don't need to wait until just before a year after your Provisional Filing Date before you file your Utility Application, and you don't need to file the Utility and PCT applications on the same day. There's a lot to be said for not waiting until the last minute...  

Time Period  Date (abbrev) Action
  First Sale, Public Use or Publication ("bar date") BD  
BD+1 year
(see note 1)
Priority Date PD File Provisional Application
PD+1 year Utility Filing Date UFD File Utility Patent Application
PD+1 year PCT Filing Date PCTF File PCT application (Chapter I) or national applications in any foreign countries in which you wish to file directly.
(WIPO has an on-line calculator for PCT dates)
UFD+90 to 120 days     Receive filing receipt from PTO. (See our page "How to read a filing receipt" for more information. 
File Information Disclosure Statement (IDS)
+5 months
International Search ISRD PCT office sends International Search Report. 
PD+18 months Publication Date PubD Both US & PCT applications are published (see note 4, below)
PD+22 months
(or ISRD+3 months)
Chapter II Date   Pay Chapter II fee and file Demand form in PCT application, to get an International Examination (see note 2, below)
UFD+9 to 18 months (on average) First Office Action OA No set date - Examiner will examine US patent application and will usually reject it. 
See our page "How to read an office action" for more information. 
OA+3 months Reply to Office Action   Can be extended to up to 6 months, but extensions will offset against any term extension due to PTO delays. 
PD+20 months

PCT National Filing under Old Rules
 (see note 2, below)

  Must file national application in those countries which have not yet changed their national rules, if no Chapter II demand was filed. 
PD+30 months PCT National Filing   Must file national applications in foreign countries  (31 months in European Patent Office and some other countries). (see note 2, below)
UFD+2½ years (on average) US Patent Application is Allowed AD  
AD+90 days Pay issue fee and publication fee, if any IFD  
IFD+90 days (on average) US Patent Issues ID Patent may now be enforced against infringers. Damages may be available for infringement between PubD and ID under some circumstances. 
ID+3.5 years First Maintenance fee due   May be paid with surcharge until ID+4 years (see note 5)
ID+7.5 years Second Maintenance fee   May be paid with surcharge until ID+8 years
ID+11.5 years Third Maintenance fee   May be paid with surcharge until ID+12 years
UFD+20 years
(see note 3)
US Patent Expires   Invention enters public domain


1.If BD was before PD, as shown here, you cannot get a patent in most countries - if you are interested in foreign patents, you should be sure to file at least a Provisional Application before your first sale or publication. Back

2. As of 1 April 2002, all PCT applications have the same deadline for national filing - 30 months from the priority date. However - note a few countries still have not adopted this change - watch our PCT News page for the latest status. In those countries, national filings must be done at 20 months unless Chapter II demand has been filed. Chapter II will remain, as an option, for those who want to demand an International Preliminary Examination. You should consult with a patent professional experienced in PCT filings (preferably Brown & Michaels) to determine if Chapter II makes sense for you or not. Back-18 mo Back-20mo Back-30mo

3. This date calculation is correct for the simple situation presented in the chart, where the utility filing date (UFD) is the earliest non-provisional filing date, and assumes that all earlier maintenance fees were paid on time. 

The expiration date of the patent is actually based on the US filing date of the first non-provisional patent application in a chain of filings, so if the patent is a continuation, continuation in part, or divisional of an earlier US application, the patent term starts at issue of the patent and ends 20 years from the earliest non-provisional filing date in the chain, assuming all of the maintenance fees are paid as they come due. If the first US application in the chain claimed priority from a foreign application, it is the actual US filing date from which the patent term is calculated, not the priority date. 

Note that patents which were in existence on June 8, 1995, or which are based on applications pending on June 8, 1995, have the 20 years from UFD term or a term of 17 years from the issue date, whichever is longer.   


January 2, 2001 - File Provisional Application
January 2, 2002 - File Utility Application based on provisional
July 12, 2003 - File continuation-in-part (CIP)* application based on Utility application
September 9, 2004 - utility application issues
December 21, 2004 - File continuation* of CIP
April 26, 2005 - File divisional* of CIP
June 4, 2005 - CIP is abandoned
September 5, 2005 - divisional issues
March 15, 2007 - continuation of CIP issues

Thus, in this example, assuming that all of the various maintenance fees are paid over their lives, all of the patents expire on the same day - January 1, 2022. However, the first application to issue has a term of 17 years 3 months, the divisional has a term of 16 years 3 months, and the continuation of the CIP has a term of  14 years 9 months.

* Definition of terms: 

CIP - an application which claims the priority of an earlier application's filing date, but adds new matter (a new embodiment or feature, etc.)

Continuation (or Request for Continued Examination (RCE) or Continuing Prosecution Application (CPA)) - an application which continues the prosecution of a pending application, but does not add any new material (to extend opportunity for argument or amend claims after final rejection).

Divisional - The rule is "one invention to a patent". If the Examiner decides that the original application claimed more that one invention, he will require the Applicant to select only one of them to which the original application will apply. The Applicant can then file one or more divisional applications, each claiming one of the other inventions which were not selected in the original application.

Any of these applications can be filed at any time if as there is a pending (unissued) application. 

For more information, see our web page "How to determine if a patent is still in force"


4. You may request earlier US publication, with payment of a fee. You may also request that your application not be published, but only if (a) the request is made at the time of filing; and (b) the application has not been, and never will be, filed PCT or in any country which publishes patent applications. Back

5. Patents filed in December 1980 or earlier do not require payment of maintenance fees. Back

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Last updated: Tue, 16 Feb 2021