What is an expired patent?

A patent expires when it either reaches the end of its maximum legal term or the patent holder misses a patent renewal payment.

In most cases, patents last up to 20 years from the filing or priority date, but this depends on the patent type and the rules of each jurisdiction. To keep a patent active, the holder must pay patent renewal fees at regular intervals.

If the holder doesn’t make those payments on time, the patent will lapse even if it hasn’t reached its full term. Once a patent expires, the protected invention becomes available for public use.