Canonical concept

CPI vs PCE

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Direct answer

CPI (Consumer Price Index, BLS) and PCE (Personal Consumption Expenditures price index, BEA) both measure US consumer-price inflation, but they aren't the same number. PCE typically runs 0.3 percentage points BELOW CPI. The Federal Reserve targets 2% PCE, not 2% CPI — a fact frequently misquoted. The main differences are weighting (housing and health care), substitution treatment, and source data (household survey vs. business survey).

Why this question matters

Most public discussion of "inflation" cites CPI because BLS releases it first and headline media run with it. But the Federal Reserve's dual-mandate inflation target — locked at 2% since 2012 and reaffirmed in the August 2020 statement on longer-run goals — is denominated in PCE, not CPI. If you're modeling Fed reaction functions, pricing real-rate exposure, or backtesting macro signals, the choice between CPI and PCE materially changes the answer. The wedge isn't large in any single month, but it compounds: 0.3 percentage points over a decade is a non-trivial drift between the same nominal series rendered two ways. The two indices also disagree on what consumers actually spend money on, which matters more than the headline gap for sector-specific work (housing, health care, durable goods).

CPI vs PCE — side-by-side

DimensionCPIPCENote
Publishing agencyBureau of Labor Statistics (BLS)Bureau of Economic Analysis (BEA)Both US Department of Commerce / Labor; methodologies diverged historically
What it measuresOut-of-pocket household consumer pricesTotal consumer expenditures including employer-paid + government-paidPCE has broader scope by design
Source dataConsumer Expenditure Survey (households)Business + administrative records (NIPA)Household self-report vs business reporting + Medicare/Medicaid data
FormulaModified Laspeyres (fixed basket, updated biennially)Fisher Ideal (chain-weighted, updates continuously)PCE captures substitution effects in near-real-time; CPI lags
Owner's-equivalent rent weight~24%~12%CPI gives shelter twice the weight; major source of recent CPI-vs-PCE divergence
Health-care weight~7%~17%PCE includes employer-paid premiums + Medicare/Medicaid; CPI is out-of-pocket only
Typical headline wedgeReference~0.3pp below CPI on average (2010-2024)Not constant; the wedge widens when housing inflates faster than health care
Release cadenceMonthly, ~10-15th of month for prior monthMonthly, ~last Friday for prior monthPCE incorporates the CPI data BLS releases two weeks earlier
Historical depthMonthly back to 1913Monthly back to 1959CPI is the only US inflation series with century-plus depth
Federal Reserve targetNot the official target2% (since 2012, reaffirmed 2020)Common misquote: media often say "Fed targets 2% inflation" implying CPI — it's PCE
Core variant (ex food + energy)Core CPICore PCEFed Chair speeches more often cite Core PCE; markets watch both
Best forHeadline cost-of-living, COLA adjustments, TIPS pricingFed policy reaction modeling, macro nowcasts, GDP deflator linkageTIPS reference CPI by indenture; PCE is the policy-relevant series

Numbers worth remembering

How to pull this data

When the Tidore macro vertical ships its `/v1/macro/<indicator>` surface, the same comparison is one HTTP call for each series. Today the canonical primary sources are BLS and BEA directly.

# Tidore (in development, M3+ release) — pull both series from one API key
curl -H "Authorization: Bearer $TIDORE_API_KEY" \
  "https://api.tidore.co/v1/macro/cpi?from=2010-01-01&to=2024-12-01"

curl -H "Authorization: Bearer $TIDORE_API_KEY" \
  "https://api.tidore.co/v1/macro/pce?from=2010-01-01&to=2024-12-01"

# Today — pull from primary sources directly (no API key required)
# BLS CPI: https://www.bls.gov/cpi/data.htm
# BEA PCE: https://www.bea.gov/data/personal-consumption-expenditures-price-index

Authoritative sources

Frequently asked questions

Does the Federal Reserve target CPI or PCE?

PCE. The Fed's 2% inflation target — locked in the January 2012 FOMC Statement on Longer-Run Goals and Monetary Policy Strategy, and reaffirmed in the August 2020 update — is denominated in personal consumption expenditures price index (PCE), specifically the all-items series. Media often shorthand this as "the Fed targets 2% inflation," which implies CPI in casual usage; the official target is PCE.

Why does PCE run lower than CPI on average?

Three structural differences. (1) Formula: PCE uses a chain-weighted Fisher Ideal index that captures substitution as consumers shift away from items whose prices rise; CPI uses a modified Laspeyres formula with a fixed basket updated every two years, which doesn't capture substitution as quickly. (2) Weighting: CPI gives owner's-equivalent rent roughly twice the weight (~24% vs ~12% in PCE), and shelter inflation has been a major driver of the gap recently. (3) Scope: PCE includes employer-paid health insurance and Medicare/Medicaid spending; CPI is out-of-pocket only.

Which inflation measure should I use for backtesting?

Depends on the question. For Fed-reaction-function models or anything pricing the federal funds rate path, use Core PCE — that's what the Fed reads. For TIPS pricing or COLA adjustments, use CPI by indenture (TIPS reference CPI-U specifically). For broad cost-of-living narratives, CPI is what the media reports. For sector-specific work (housing, health care), the weighting differences make one or the other dominant by topic.

How big is the typical CPI-PCE wedge?

About 0.3 percentage points on average over 2010-2024, with PCE running below CPI. The wedge isn't constant — it widens when housing prices outpace health-care prices (because CPI overweights shelter), and narrows in the opposite regime. In some 12-month windows the wedge has been near zero; in others it's exceeded a full percentage point. Always check the specific window before treating "0.3pp" as a universal constant.

When do CPI and PCE get released each month?

CPI: typically the 10th to 15th business day of each month, for the prior month's data (BLS publishes a release calendar a year in advance). PCE: typically the last Friday of each month, for the prior month's data — PCE incorporates the CPI release that preceded it by roughly two weeks, so PCE always lags CPI within any given month.

Is one more accurate than the other?

Neither is more accurate; they measure different things. CPI measures out-of-pocket household consumer prices for a fixed-weight basket; PCE measures total personal consumption (including employer and government payments) for a chain-weighted basket. Both are correct for their respective questions. The distinction matters most when reading Fed minutes (Core PCE) versus reading TIPS pricing (CPI-U).

See also