Consumer Price Index (CPI)
- The main measure of inflation used by the United States, that is calculated by the Bureau of Labor Statistics (BLS). This measure is used by the government to report inflation rates, and make according changes in programs such as social security.

CPI reports the price of a "market basket" of 300 consumer goods and services purchased by a typical urban consumer. Based on spending patterns in a specific period. BLS updates the basket every 2 years so that it reflects the most recent patterns, and captures the inflation or deflation being experienced at the moment.

CPI =(Price of the most recent market basket in the particular year / Price estimate of the same market basket in base year) X 100%