When the news reports that inflation was 3% last year, it usually means the Consumer Price Index rose 3% over twelve months. That single number drives Social Security raises, tax brackets, union contracts and Federal Reserve decisions. It also often feels wrong to people paying the bills. Both things can be true.
The Consumer Price Index
The Bureau of Labor Statistics publishes the CPI every month. Data collectors record prices for a fixed basket of goods and services, from groceries and gasoline to rent, car insurance and haircuts, in urban areas across the country. Each item is weighted by how much households spend on it, based on the Consumer Expenditure Survey. Housing is the largest category, roughly a third of the index.
- CPI-U covers urban consumers, more than 90% of the population. It is the headline number.
- CPI-W covers urban wage earners and clerical workers and is used to set Social Security cost-of-living adjustments.
- Chained CPI adjusts for people switching to cheaper substitutes and has been used to index federal tax brackets since 2018.
- Core CPI excludes food and energy, which swing sharply, to show the underlying trend.
How housing is counted
For homeowners, the CPI doesn’t use house prices or mortgage payments. It uses “owners’ equivalent rent,” an estimate of what owners would pay to rent their own home. Because rents on existing leases change slowly, the housing component lags behind market rents by many months. That lag is one reason official inflation can stay high after market rents cool, or stay low after they jump.
The PCE index: what the Fed watches
The Bureau of Economic Analysis publishes the Personal Consumption Expenditures price index. It covers a broader range of spending, including what employers and government pay on households’ behalf for health care, and it updates its weights more often. PCE inflation usually runs a few tenths of a point below CPI. The Federal Reserve’s 2% inflation target is defined in terms of PCE. See what the Federal Reserve does.
Why your inflation is different
- Your basket isn’t average. A renter who drives a lot and a homeowner who works from home face different price changes.
- Frequent purchases loom large. People notice grocery and gas prices weekly but rarely see price changes on electronics, which have often fallen.
- Price levels don’t come back down. When inflation falls from 8% to 3%, prices are still rising, just more slowly. Most people compare today’s prices with what they remember, not with last year’s.
- Quality adjustments. BLS adjusts for some quality changes, such as a faster laptop at the same price. Those adjustments are reasonable but invisible to shoppers.
The BLS publishes CPI data by region and category, and its CPI inflation calculator lets you compare prices across years.