In October 2011, new rules governing debit card interchange fees became effective in the United States. These rules limit the maximum permissible interchange fee that an issuer can charge merchants for a debit card transaction. Using new data from the Federal Reserve of Boston, Richmond, and San Francisco 2012 Diary of Consumer Payment Choice, this article provides simple calculations that identify the transaction values by consumer expenditure category for which interchange fees became higher and lower under the new rules. (JEL G28)