Once a month, the Bureau of Labor Statistics turns four weeks of price collection into a single press release, and for a few minutes every financial outlet runs a version of the same headline. That release is the Consumer Price Index report, and everything on this site’s current inflation rate page and monthly report archive traces back to it. Reading one well takes about two minutes once you know which numbers matter and which ones the market already priced in.
When it lands
The CPI report publishes on a fixed monthly schedule, usually the second week of the following month, at 8:30 a.m. Eastern, the same release slot the BLS uses for jobs and producer-price data. This site’s report archive adds each new release automatically within hours of publication, so checking there is faster than waiting on the BLS calendar page to refresh.
Headline vs. core
Every release reports two twelve-month rates. Headline CPI covers the full basket, including food and energy, the categories that swing hardest from month to month on weather and oil markets. Core CPI strips those two categories out, on the reasoning that a bad wheat harvest or an OPEC production cut says little about the broader trend in prices. Reporters lead with headline because it is what households actually pay at the register. The Federal Reserve weighs core more heavily internally, because it moves less erratically and gives an earlier read on where headline is likely to settle once a commodity spike fades.
Neither number is “the real” inflation rate; they answer different questions, the same way CPI and PCE do.
Month-over-month vs. year-over-year
Two more figures do the actual predicting. The twelve-month rate compares this month’s index with the same month a year ago, which cancels out seasonal patterns by construction (comparing August with August) and is the number printed in headlines. The month-over-month rate compares this month with last month and shows turning points faster, since a slowdown can take most of a year to fully show up in the twelve-month figure after it starts. Most news coverage quotes the seasonally adjusted month-over-month change, stripped of predictable patterns like January sales and summer gas demand; the not-seasonally-adjusted version, the one behind this site’s report pages and calculator, tracks the raw index instead.
What doesn’t change after publication
The CPI is a not-seasonally-adjusted series and, unlike PCE, it is never revised once published. Whatever number prints this month is the number that stays in Social Security’s math, TIPS coupons, and every lease or contract escalator tied to CPI, permanently.
A worked example: June 2022
Take the report covering June 2022, the month the cycle’s twelve-month rate peaked. Headline CPI had climbed 9.1% over the previous twelve months, a level not seen since 1981, while core CPI, which excludes food and energy, was running cooler at 5.9%. A month earlier the twelve-month rate had been 8.6%, so the June release also showed the pace still accelerating, something only visible by comparing releases side by side. Against the prior month, not seasonally adjusted, the index itself moved about 1.4%, the largest single-month jump of that entire surge. No one of these three numbers tells the full story; read together, they show a rate still climbing, running hot even with gas and groceries stripped out, and doing so faster than the month before.
What moves once the number drops
The release resets a chain of numbers downstream of it. The annual Social Security COLA is built from a specific three-month average of the CPI-W variant, so cost-of-living increases firm up, or don’t, release by release. TIPS and I Bond rates adjust off the same base index. And while the Fed’s 2012 statement of longer-run goals formally targets PCE rather than CPI, the CPI report publishes roughly two weeks earlier each month, so it is usually what moves rate-cut odds and bond yields first.
Checking it yourself
- The report archive lists every release since 2021, newest first, with headline and core side by side.
- The current inflation rate page always reflects the latest published number, no new article required.
- The methodology page documents the exact BLS series and formulas this site runs against every release.
One report tells you where prices stand. A run of four or five, the way the 2022 surge shows, tells you where they’re headed, and that trend is the number that actually matters for a household budget or a rate decision.