How to Calculate Patent Expiration

Instructions
Things You'll Need:

* Patent database

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Search for patents using online patent searches through the U.S. Patent and Trademark Office or through other patent search sites such as Google Patent Search, Patent Lens or Free Patents Online to get an idea of patents similar to your idea. Search by keywords to conduct a general patent search for patents similar to your product. Search by patent number if you know exactly which patent you are looking for.
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For patents filed on or after June 8, 1995, calculate the patent expiration date as 20 years from the time the patent was filed. For example, if an inventor filed a patent on July 12, 1996, the patent will expire on July 12, 2016.
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Calculate patent expiration dates for patents filed before June 8, 1995 by comparing filing and issue dates. Add 17 years to the patent issue date. Add 20 years to the original patent filing date. Calculate the patent expiration date as the later of the two dates.

For example, if an inventor filed for a patent on January 10, 1995 and the patent was issued on June 20, 1999, the patent would expire on June 20, 2016 (17 years after the patent issue date) since this date extends beyond January 10, 2015, which is 20 years from the original patent filing date. If the inventor filed for a patent on January 10, 1995 and was issued the patent on March 14, 1996, the patent would expire on January 10, 2015, or 20 years from the patent filing date, since this date extends beyond March 14, 2013, or 17 years from the patent issue date.
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Calculate patent expiration dates for patents based on a previous patent application using the first patent filing date. For example, if an inventor filed for a patent on January 10, 1995, but the patent was based on a patent application that was filed on February 14, 1992, use February 14, 1992 as the filing date for expiration calculation purposes.