The term of a patent is the maximum period during which it can be maintained into force. It is usually expressed in number of years either starting from the filing date of the patent application or from the date of grant of the patent. In most patent laws, renewal or maintenance fees have to be regularly paid in order to maintain the patent into force. Otherwise the patent lapses before its term.
Significant international harmonization of patent term across national laws was provided in the 1990s by the implementation of the WTO's Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPs Agreement). Article 33 of the TRIPs Agreement provides that the
"The term of protection available [for patents] shall not end before the expiration of a period of twenty years counted from the filing date."
Consequently, in most patent laws nowadays, the term of patent is 20 years from the filing date of the application. This however does not forbid the states party to the WTO from providing, in their national law, other type of patent-like rights with shorter term. Utility models are an example of such rights. Their term is usually 6 or 10 years.