What is PCE vs CPI?

The Personal Consumption Expenditures (PCE) price index and the Consumer Price Index (CPI) are the two primary measures of consumer inflation in the United States. While both track changes in the prices paid by consumers, they differ in methodology, scope, and weighting, which causes them to give systematically different readings. The Federal Reserve officially targets 2% annual inflation as measured by the PCE index, not CPI.

The most important methodological difference is the substitution effect. CPI uses a fixed basket of goods and services that is updated periodically, assuming consumers buy the same items regardless of price changes. PCE uses a chain-weighted formula that accounts for consumers switching to cheaper alternatives when relative prices change. For example, if beef prices spike, PCE reflects consumers shifting to chicken, while CPI continues pricing the original beef-heavy basket. This makes CPI a cost-of-goods index and PCE a cost-of-living index.

Coverage and weighting also differ significantly. CPI only covers out-of-pocket expenditures by urban consumers, while PCE includes spending on behalf of consumers by employers and government (such as employer-paid health insurance and Medicare). As a result, healthcare has a much larger weight in PCE than in CPI. Conversely, shelter (rent and owners' equivalent rent) has a much larger weight in CPI, roughly 36% compared to about 16% in PCE. This shelter weight difference is a major reason CPI often runs 20 to 40 basis points higher than PCE annually.

For investors and analysts, both measures matter. CPI is used for TIPS indexation, Social Security cost-of-living adjustments, and tax bracket inflation adjustments, making it directly relevant to personal finance. PCE drives Fed policy decisions, making it the measure to watch for anticipating rate changes. When CPI and PCE diverge significantly, it usually reflects shelter costs or healthcare spending, and understanding which measure is driving the divergence is essential for correctly interpreting the inflation outlook.