How Many Patents Are Currently Alive?

In previous blog posts, I’ve discussed patent maintenance fees and patent term adjustment, both of which may affect how long a patent may remain in force after issuance. In my experience, people seem to forget that not every patent survives up to its life expentancy due the failure of the patent holder to pay maintenance fees (and that some patents may outlive the typical patent lifespan because of patent term adjustment).

A recent blog post on Patently-O shows Dennis Crouch’s attempt to calculate how many patents are currently in force. He came up with 2.1 million. Thus, out of the roughly 8.2 million US patents that have been granted, about one quarter of them could still be asserted against accused infringers.