The Consumer Price Index (CPI) in the United States is a measure of the average change over time in the prices paid by urban consumers for a market basket of consumer goods and services. It is used as a gauge of inflation and is one of the most widely used measures of economic activity.
The CPI is determined and published by the Bureau of Labor Statistics (BLS), a U.S. Department of Labor division. The BLS collects price data every month from thousands of retail and service businesses, as well as from housing units. The data is then analyzed to produce the CPI.
The period of determining the CPI is typically monthly, with the BLS releasing a report on the CPI around the middle of each month.
The CPI is based on the prices of goods and services purchased by urban consumers, including food, clothing, shelter, transportation, medical care, and other goods and services. The CPI is calculated by comparing the cost of the market basket of goods and services in the current period to the cost of the same basket in a base period and then expressing that change as a percentage. The CPI is also broken down into various sub-indexes, such as core CPI, which excludes volatile components like food and energy.