Read a CPI release in four passes: the 12-month all-items change (not seasonally adjusted), the one-month seasonally adjusted change, the same two numbers for core CPI, and then Table A’s component lines (shelter, energy, food, goods, services) to see what drove the month.
Before the release: know the schedule
The BLS publishes the Consumer Price Index at 8:30 a.m. Eastern time, typically around the middle of the month after the reference month. September data arrive in October, for example. The dates are fixed a year in advance on the BLS CPI schedule, and our release calendar lists the next one. The figures are embargoed until release; no official number exists before 8:30 a.m.
Pass 1: the headline paragraph
The first paragraph of the news release states two numbers for the all-items CPI-U:
- the one-month change, seasonally adjusted, for example “increased 0.6 percent on a seasonally adjusted basis”;
- the 12-month change, not seasonally adjusted, for example “the all items index increased 3.7 percent before seasonal adjustment.”
These are the two figures most headlines quote. They come from different series on purpose: the monthly number needs seasonal adjustment; the annual number does not, because a full year contains every season once.
Pass 2: core CPI
The release then gives the same two statistics for “all items less food and energy”. The monthly core change is the cleanest single read on underlying momentum in a given month; the 12-month core rate shows the trend over a year. See core vs headline inflation for why both exist.
Pass 3: Table A — what drove the month
Table A of the release lists seasonally adjusted monthly changes for the main components over the past six months, plus the unadjusted 12-month change. The lines worth scanning, in order of weight:
| Component | Why it matters |
|---|---|
| Shelter (rent, owners’ equivalent rent) | Largest single component, roughly a third of the index; slow-moving |
| Energy (gasoline, electricity, natural gas) | Most volatile; often explains headline vs core gaps |
| Food at home / away from home | Large weight; food away from home tracks wages in restaurants |
| Commodities less food and energy | Goods such as cars, apparel, household furnishings |
| Services less energy services | Includes shelter, medical care, transportation services |
A month in which headline jumps but core is calm is usually an energy story. A month in which core is strong and shelter is calm points to other services or goods.
Pass 4: check the six-month row and annualise
Table A shows six months of monthly changes side by side. Adding them up mentally gives a sense of trend. To compare with a 12-month rate, annualise: a 0.3% monthly change compounds to about 3.7% a year ((1.003)^12 − 1). Our CPI indicator page computes three- and six-month annualised rates from the seasonally adjusted index so you do not have to.
Common misreadings to avoid
- Mixing NSA and SA. Do not compute a monthly change from the unadjusted index and compare it with the seasonally adjusted headline monthly figure.
- Treating the index level as a rate. An index of 336.9 is not 336.9% of anything meaningful by itself; only percent changes are.
- Comparing with PCE without adjustment. The Fed’s target uses the PCE price index from the Bureau of Economic Analysis, which has different weights and coverage. CPI usually runs somewhat higher.
- Over-reading one month. Single-month changes are noisy; the BLS notes standard errors for its estimates.
- Assuming revisions. Unadjusted CPI is final when published. Only seasonally adjusted figures change, once a year in February.
Where else to look
The BLS also publishes Real Earnings at the same time as CPI, which deflates average hourly earnings by the CPI. Our average hourly earnings page shows a simple real-wage calculation; the guide on real vs nominal wages explains the method.
A ten-minute routine
- Note the release time and reference month.
- Write down the four numbers: headline monthly SA, headline 12-month NSA, core monthly SA, core 12-month NSA.
- Compare each with the prior month on our indicator pages.
- Scan Table A for shelter, energy, food and core goods.
- Annualise the latest three months of core for momentum.
- Check the release for any methodology notes or data-collection caveats in the technical note.
Frequently asked questions
- What time is CPI released?
- The BLS publishes the CPI news release at 8:30 a.m. Eastern time on the scheduled date, usually in the middle of the month following the reference month.
- Why do monthly and annual CPI numbers use different series?
- BLS reports the 12-month change from the unadjusted index and the 1-month change from the seasonally adjusted index, because seasonal effects matter month to month but cancel over a full year.
- Can CPI be revised?
- Unadjusted CPI data are not revised after publication. Seasonally adjusted data are revised each February for the previous five years when new seasonal factors are calculated.