Generally speaking, a utility patent will expire 20 years from its filing date. The filing date extends back to the earliest related patent application. The earliest related patent application will include foreign applications. However, provisional applications are excluded from the calculation.
There are also several factors that can affect the term of a patent. These factors include, whether the patent claims priority to other applications, whether the patent is subject to a terminal disclaimer, whether the U.S. Patent and Trademark Office added any patent term, and whether the patent owner has paid the necessary maintenance or annuity fees.
Regardless of the type of patent, all patents will eventually expire. Once expired, the disclosed information disclosed becomes part of the public domain. This means that the information contained in the patent is public property and can be used freely by anyone. To confirm, you cannot refile or renew your patent after it runs its full 20-year term (15-year if a design patent).