Consumer Price Index (CPI)

What the CPI measures

The Consumer Price Index (CPI) tracks the change over time in the prices that households pay for a fixed basket of goods and services: food, fuel, rent, cars, clothing, medical care, airfares, haircuts and much more. It is the most widely quoted measure of inflation in the United States, and it is the inflation report that usually draws the strongest reaction from markets.

The U.S. Bureau of Labor Statistics (BLS) builds the index from prices its staff collect each month in person, by phone and online, weighted by how much consumers actually spend on each category.

Who publishes it and when

BLS publishes the CPI monthly, at 8:30 AM Eastern Time, roughly two weeks after the end of the month it covers. The exact days are set in advance on the BLS release calendar; the schedule for upcoming releases is shown on this page. The official release and documentation live on the BLS CPI home page.

The numbers traders watch

A CPI release contains hundreds of indexes. Most coverage boils down to four figures:

• Headline CPI, month over month. The seasonally adjusted change in the all-items index from the prior month. This is the number most closely compared with forecasts.
• Headline CPI, year over year. The change from the same month a year earlier. It is the figure most people mean when they say “inflation is running at…”.
• Core CPI. The all-items index excluding food and energy. Food and fuel prices swing for reasons that often have little to do with the broader economy (weather, harvests, oil supply), so core is treated as a better guide to underlying inflation.
• Core month over month. Many traders consider this the single most important number in the release, because it is the freshest read on whether underlying price pressure is speeding up or slowing down.

Beyond those, analysts dig into shelter (which includes rent and owners’ equivalent rent, the BLS estimate of what homeowners would pay to rent their own home), services excluding shelter, used and new vehicles, and medical care.

CPI-U versus CPI-W

The headline index is the CPI for All Urban Consumers (CPI-U), which BLS says covers more than 90 percent of the U.S. population. The CPI for Urban Wage Earners and Clerical Workers (CPI-W) covers a narrower group and is the index used for Social Security cost-of-living adjustments. Markets focus on CPI-U.

How markets commonly react

The usual story runs like this. A hotter-than-expected print (inflation higher than forecast) raises the odds that the Federal Reserve keeps interest rates higher for longer. Treasury yields tend to rise, the dollar tends to firm, and stocks, especially those whose value rests on profits far in the future, tend to come under pressure. A cooler print is said to do the reverse.

That pattern is a tendency, not a rule. The reaction depends on what was already expected, on which part of the report surprised (a jump in energy prices is read differently from a jump in core services), on where the Fed is in its cycle, and on what else is happening that week. Sometimes a “bad” number produces a rally because positioning was even more pessimistic. The first move after 8:30 AM is also often reversed later in the session. No single release reliably sets the direction of any market.

Revisions and seasonal adjustment

Unlike many economic reports, the unadjusted CPI is generally treated as final when first published, because it is written into contracts, pension adjustments and tax brackets. BLS corrects it only in rare cases of error.

Seasonally adjusted figures are a different matter. BLS re-estimates its seasonal factors once a year and can revise previously published seasonally adjusted data for up to five years. That means the month-over-month pattern you remember can look slightly different after the annual update.

Common misreadings

• Confusing the level with the rate. A falling inflation rate means prices are rising more slowly, not that prices are falling.
• Ignoring the base effect. The year-over-year rate can move sharply simply because of an unusual month a year earlier dropping out of the comparison.
• Over-reading one month. Single months are noisy. Analysts look at three- and six-month trends before drawing conclusions.
• Treating CPI as the Fed’s target. The Fed defines its 2 percent goal using a different measure, the PCE price index. See the PCE explainer and the guide comparing CPI, PPI and PCE.

Frequently asked questions

What time does the CPI report come out?

At 8:30 AM Eastern Time on the release date, before the U.S. stock market opens. Futures, Treasuries and currencies react immediately.

What is the difference between core CPI and headline CPI?

Headline CPI includes everything in the basket. Core CPI removes food and energy, which are volatile, to give a steadier read on underlying inflation. Both matter, but core usually gets more weight in market commentary.

Does the CPI get revised?

The unadjusted index is generally final when published. Seasonally adjusted figures can be revised for up to five years when BLS updates its seasonal factors each year.

Why do markets sometimes rally on a high CPI number?

Because prices reflect expectations. If traders had braced for something worse, or the details looked better than the headline, a high number can still be read as a relief.

Explainer updated November 13, 2026.