PCE vs CPI: Why America Has Two Inflation Numbers
Published . Methodology and comparison-period correction: .
The original June 2026 article paired May CPI with April PCE. Those different reference months do not isolate a same-month index gap. This correction removes the release forecasts and policy predictions; it explains the measures and links to their publishers for current readings.
CPI and PCE both measure consumer-price changes, but their coverage, expenditure weights and formulas differ. Neither should be interpreted without its period and definition. The BEA reconciliation separates formula, weight, scope and other effects; a difference between two published rates is not automatically explained by one of them.
Coverage and weights
CPI-U covers urban households' out-of-pocket spending. PCE also includes purchases made on households' behalf, such as employer- and government-paid healthcare, and spending by nonprofit institutions serving households. That broader coverage changes the relative weights of categories such as healthcare and housing. Category weights belong to a defined period; they are not permanent percentages.
| Feature | CPI-U | PCE price index |
|---|---|---|
| Coverage | Out-of-pocket spending by urban households | Spending by and on behalf of households and nonprofit institutions serving households |
| Expenditure weights | CPI-U weights are updated annually; they remain fixed within that year | Chain weights reflect changing expenditure patterns |
| Price aggregation | Geometric means in most basic item-area indexes; a modified Laspeyres formula at the aggregate level | Fisher-Ideal chain-weighted aggregation |
| Substitution | Allows substitution within most item categories; CPI-U does not incorporate substitution across categories in its aggregate formula | The chain formula accommodates changing expenditure patterns across categories |
| Price inputs | BLS price collections, with expenditure information used for weights | Many component price indexes are derived from BLS consumer and producer price indexes |
Substitution within and between categories
CPI does not universally assume unchanged consumption. Since 1999, most basic item-area indexes have used geometric means that allow substitution within an item category as relative prices change. CPI-U's higher-level formula does not incorporate substitution between categories. The separate chained CPI, C-CPI-U, is designed to address that broader substitution.
PCE uses Fisher-Ideal chain-weighted aggregation and changing expenditure patterns. This does not mean it measures every household's personal cost of living or captures all substitution perfectly. Nor is PCE an independent survey of every price: BEA derives many component price indexes from BLS consumer and producer price indexes.
Compare the same period and the same kind of rate
A release date is when a figure was published; its reference month is the period it describes. May CPI and April PCE therefore combine differences in measurement with differences in time. To examine a same-month CPI–PCE gap, select the same month and compare headline with headline or core with core. Keep year-over-year, monthly and annualized changes separate, and check seasonal treatment and revisions.
Use the BLS CPI releases and BEA PCE releases for published readings. BEA's Table 9.1U comparison provides a reconciliation of the indexes. This article does not supply a current inflation rate or a rate-decision forecast.
The Fed's target does not mean it ignores CPI
The Federal Reserve states its longer-run 2% inflation objective in terms of the annual change in the PCE price index. It also monitors CPI and other price indexes. The target is a defined measure, not a rule to choose whichever reading is lower. Core measures can help assess underlying trends, but a single index difference does not determine a policy decision, an exchange rate or a country's GDP.
Questions about these measures
Does CPI assume that consumers never substitute?
No. Most basic CPI indexes use geometric means that allow substitution within an item category. CPI-U’s aggregate formula does not incorporate substitution between categories; the separate chained CPI is designed to address that broader substitution.
Can May CPI and April PCE measure the gap for one month?
No. They cover different reference months. Match the reference period, headline or core definition, rate calculation, seasonal treatment and release vintage before interpreting an index difference.
Does the Fed ignore CPI and target whichever number is lower?
No. The Fed monitors several price indexes, including CPI. Its stated longer-run 2% inflation objective uses the annual change in the PCE price index; that is a defined measure, not a rule for choosing the lower reading.
Sources for this correction
- BLS: Common misconceptions about the CPI
- BLS: Chained CPI, substitution and annual expenditure weights
- BEA: Reconciling CPI and PCE differences
- BEA: PCE prices and Fisher chain-weighted aggregation
- Federal Reserve: Evaluating inflation across several indexes
- Federal Reserve: The longer-run 2% PCE inflation target
Explore sourced economic series, the US economy profile and country comparisons. International annual inflation comparisons use their own definitions and periods; they are not substitutes for a matched monthly CPI–PCE comparison.