This invention provides methods, apparatus, and systems for classifying addresses. An address is evaluated based upon a postal code or standardized postal code, such as a U.S. Postal Service ZIP+4 code, serving the address. If the address cannot be classified based on the standardized postal code, the address is classified based on additional information, such as a U.S. Postal Service delivery point code. A mailer may then determine whether the address is a business or residential (or non-business) address. Furthermore, a mailer may predict when surcharges may apply and compare the rates of various carriers.