A FedEx package can be tracked without a tracking number by using other reference information, such as the invoice number or another reference number given at the time of shipment. Packages shipped through UPS also can be tracked when a tracking number is not available by using alternative reference information provided when the shipment is created.
Only certain types of packages sent through the U.S. Postal Service use tracking numbers. For packages that are lost and have no tracking number available, a search request may be filed through local post offices. To begin the search, the value of the package contents must be at least $25, as of 2014. The person requesting the search provides the delivery and return addresses along with phone numbers for the recipient and the sender.
As of 2014, tracking of packages typically uses bar codes, which are read by a machine. Information on the package location is maintained in a database, which can be accessed online through package-delivery companies. Package tracking is an example of track and trace, a way of determining the past, current and future locations of a product. Track and trace is used in the fields of logistics and product distribution. Track-and-trace systems typically include the positions of vehicles and shipping containers. They provide the ability to retrieve status reports in real time. Shipping companies, such as FedEx and UPS, implement track-and-trace systems by reporting arrival and departure of packages at certain locations.