As an independent software programmer it is very tricky and time consuming to understand these patents. I would say it is impossible for me. Do software patents have a lifetime? If they do, it would mean, that in a few years we do not have to care about software patents anymore.

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    Is there any evidence it is different from normal patents? Sep 21, 2012 at 8:46
  • @AlexChamberlain, The usual "this but" and "this but, but, but" kind of fine print law documents use is enough evidence for explicit "evidence it is different from normal patents" to be unneeded.
    – Pacerier
    Oct 10, 2015 at 20:32

5 Answers 5


One problem with our patent system is that it is actually somewhat difficult to figure out whether a patent is still in force. There are a few steps that get usually you to the answer:

  • If it is a design patent, then the patent remains in force for 14-years from the patent issue date. Case closed. Edit: Since May 13, 2015, the term for a design patent is 15 years from the issue date. Here is the requisite USPTO page.

The following steps apply to Utility Patents in the US. The same rules apply to all utility patents regardless of whether the subject is a software patent or something else.

  • If the patent application was filed on or after June 8, 1995, the starting patent term is 20 years. This accounts for the vast majority of patents in force today. The 20 year term is calculated based upon the priority filing date, not counting provisional application or the original filing in a foreign country. Patents that issued before the 1995 changeover have a term of 17 years from the patent issuance date. Patents that were filed before the 1995 date but issued afterwards get the longer of the two terms.
  • Most patents issued in the past decade have an added term adjustment (PTA) due to delays in examination at the USPTO. This adjustment can be found on the face of the patent in terms of the number of days that should be added to the patent term.
  • To stay in force for the entire 20 year term, utility patent owners must pay three maintenance fees. If one of those fees is not paid then the patent will be seen as expired and no longer enforceable. Most patentees do not pay all three fees - thus most patents expire before completion of the 20 year term.
  • When a patent owner has a family of related patents, the USPTO often requires that the patentee file a "terminal disclaimer" that (partially) ensures that the patents all expire at the same time. These terminal disclaimers sometimes impact the patent term, but they can only be found by digging through the file history.
  • There are a few other ways to extend the effective patent term, but most of these are related to pharmaceutical and other medical related patents rather than software.

If you follow these steps then you'll get to the right answer in the vast majority of cases.

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    This should really be the accepted answer. It's much more complete/thorough. Sep 21, 2012 at 16:44
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    Very good answer, one small correction: any patent in force on the 1995 date or patent application filed before the 1995 date gets the greater of 17 from issue or 20 from earliest priority. See uspto.gov/web/offices/pac/mpep/s2701.html
    – user1023
    Sep 21, 2012 at 17:43
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    thank you very much for that answer, these are very detailed information. Is there a searchable/filterable database that holds all patents?
    – user61664
    Sep 21, 2012 at 21:41
  • I updated this otherwise excellent answer to reflect the change in design patent term since 2015.
    – Eric S
    Jan 18, 2018 at 23:05
  • How about if the patent was adjudicated to be invalid? Dec 26, 2020 at 5:52

In the US, software patents are same as normal patents. However there is another type of patent called the design patent which is for industrial designs. User Interfaces can be protected by design patents e.g., this one here is for Facebook's UI.

To answer the question, in the US -

I am not very sure about the position in rest of the world.

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    A good resource is Maxval's calculator (maxval-ip.com/patenttool/PatentTermCalculator.aspx). Note that it's not 100% accurate (since there are sometimes adjustments for patent office delay) and I would always check the priority dates to make sure there's no hidden or malformed priority claim. Overall though that site is good to get a estimate within a year or so.
    – aosik
    Sep 21, 2012 at 16:55
  • @aosik, So what tools do real lawyers use?
    – Pacerier
    Oct 10, 2015 at 20:36

According to this article on Wikipedia, software patents have a lifespan of around 20 years.


It can be complicated - you have to look for some clues on the front page of the patent - but generally it's 20 years after the filing date. For more info Google for "patent expiry".

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    Welcome to Stack Exchange. Have you got an example you can cite? Maybe another website that says the same thing? I'm sure you're right, but we should aim to have references in place. Sep 21, 2012 at 8:54
  • Here is a page with more details of how it's calculated with some examples: patentlens.net/daisy/patentlens/2973.html
    – dspig
    Sep 24, 2012 at 12:33

There is no such thing as a software patent in the U.S. . Software per se is not a category of patentable subject matter.

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    “Software patent” is an informal name for patents on algorithms (which are allowed in most countries, generally with some requirement that the algorithm be for a practical purpose, which is not very restrictive). Sep 21, 2012 at 22:05

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