U.S. passports are valid for ten years if the passport holder was 16 or older when he obtained his passport and for five years if the passport holder was 15 or younger at that time. The front of a passport card or the data page of a passport book shows the issue and expiration dates.
U.S. passport applications take four to six weeks to process. U.S. citizens may renewal by mail if the current passport holder is over the age of 16 and has a passport that is less than 15 years old and undamaged. Applicants under the age of 15 must apply for a passport in person. The U.S. Department of State issues passport renewals even if a passport has not yet expired. Some countries require passports that are valid for six months beyond traveling dates, and many airlines prevent travelers from flying if they don't meet this requirement.
The U.S. Department of State provides detailed information about U.S. passport regulations and rules online at State.gov. Additionally, the U.S. Passports and International Travel Web page offers information about passport renewal, processing times, lost passports and application status. Information about where to apply for passports and contact information for the National Passport Information Center is also available.