Informal entries cover personal shipments, commercial shipments and mail shipments that are being entered for consumption, i.e. for use or sale. In most cases informal entry can be used if the merchandise is valued at $2000 or less. There are some exceptions such as textiles, certain types of footwear and other goods subject to quota/visa restrictions. Personal shipments valued over $2000 will also require a formal entry. The difference between an informal entry and a formal entry is the bond requirement and the liquidation process. Liquidation is the final computation of duties or drawback accruing to an entry and is the final step in the entry process.

Formal entries are generally commercial shipments supported by a surety bond to ensure payment of duties and compliance with Customs requirements. A bond is like an insurance policy that is payable to Customs in the event that the importer does not comply with import requirements. Having a bond on file, allows an importer to take possession of his merchandise before the payment of duties, taxes and fees. Bonds can be obtained from a surety, which is an insurance company that has been authorized by the Treasury Department to write Customs bonds.

A port director can require a formal entry for any importation if he or she deems it necessary for the protection of the revenue or for admissibility or enforcement issues.

Goods admitted as informal entries do not require the posting of a bond and goods are liquidated on the spot. After the importer receives notification of the arrival of merchandise from the carrier and it is determined that all shipping charges are satisfied an invoice is presented to Customs. When an informal entry is being made, the inspector, not the importer, is responsible for determining the classification number of the goods being imported. The inspector also completes the Customs forms used for informal entry.