How many patents have terminal disclaimers (i.e., truncation in their time to expiry)? I am looking for a percentage of the total population of patents granted. A rough estimate + source is good enough.

Is there an easy way to tell if a specific patent have been terminally disclaimed?

  • I assume the original software is terminal by just making any needed modification of the software. Old software + Plus my new software = New Software... previous software is thus "terminated" and "new" software is created. The new software succeeds the old software, until itself is also improved. The cycle continues until E-Tern-I-Ty.
    – user18592
    Commented Mar 1, 2017 at 15:43

3 Answers 3


The USPTO put out a working paper in June 2015 titled "The USPTO Historical Patent Data Files: Two centuries of invention". In it they state "Internal estimates suggest that 11.9% of patents granted in 2012 contain terminal disclaimers. This rate has increased from 3.4% in 1990; thus we expect this to become an increasing problem with respect to calculating the expiration date of patents in the future." See footnote 36, page 12.

  • +1 for a fantastic find.
    – Maca
    Commented Mar 2, 2017 at 9:35

As very good source is the patent office's site itself. http://www.uspto.gov/sites/default/files/patents/law/How_to_Locate_Patent_Term_Information.docx That tells you (in plain English with pictures) how to step-by-step to figure out if it is TD and why. As for an estimate, I can't figure that out.


You can also go to http://patft.uspto.gov/ and insert patent number in the full-page image. You retrive the patent specification as published and if there is a terminal disclaimer you will find it printed clearly on the first page, left column.

No source for statistics but I am guessing the more patents there are in the same family, the more likely it will be that they will be terminally disclaimed.

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