The Consumer Price Index (CPI) is a measure of the average change over time in the prices paid by urban consumers for a fixed market basket of consumer goods and services from A to Z. The CPI provides a way for consumers to compare what the market basket of goods and services costs this month with what the same market basket cost a month or a year ago. The Consumer Price Index is the most widely used measure of inflation. It provides information about price changes in the Nation's economy to government, business, labor, and private citizens, and is used by them as a guide to making economic decisions.