The consumer price index, or CPI, is the main U.S. measure of inflation: it tracks the average change over time in the prices consumers pay for a representative basket of goods and services. The Bureau of Labor Statistics (BLS) publishes it every month, and its latest report showed consumer prices up 3.7 percent in the 12 months to September 2026.
Because the CPI feeds into interest-rate expectations, Social Security payments, tax brackets and wage negotiations, the monthly release is one of the most closely watched economic reports in the calendar. This guide explains what the index covers, how to read the report and when the next one is due, with the latest figures in a dated section at the end.
What does the CPI measure?
The BLS sorts everything consumers buy into more than 200 categories, grouped into eight major groups: food and beverages, housing, apparel, transportation, medical care, recreation, education and communication, and other goods and services. Prices are collected each month in 75 urban areas from about 6,000 housing units and roughly 22,000 retail establishments, including supermarkets, department stores and hospitals.
Each category is weighted by its share of household spending, based on the government’s Consumer Expenditure Surveys. Sales and excise taxes tied to purchases are included. Income and Social Security taxes are not, and neither are investments such as stocks, bonds, real estate and life insurance, which the BLS treats as savings rather than day-to-day consumption.
The headline index, the CPI for All Urban Consumers (CPI-U), covers more than 90 percent of the U.S. population. It is expressed as an index level with 1982-84 set at 100; in September 2026 it stood at 336.940. Most coverage focuses on percent changes rather than the level itself. The BLS also cautions that the CPI reflects an average household, so an individual’s own inflation rate can be higher or lower depending on what that person buys.
What is the core inflation rate?
Core inflation usually refers to the CPI for all items less food and energy. The BLS notes that some users prefer it because food and energy prices are relatively volatile, and they want a read on the underlying trend.
September 2026 shows why the distinction matters. Gasoline prices rose 9.1 percent in the month on a seasonally adjusted basis and accounted for more than half of the overall increase, according to the BLS. Headline CPI rose 3.7 percent over 12 months, while core CPI rose 2.6 percent.
