How to Read the CPI Report: Headline, Core and the Surprise

The Bureau of Labor Statistics (BLS) published the September 2026 Consumer Price Index (CPI) report at 08:30 Eastern Time on 14 October 2026. US consumer prices were 3.7% higher than a year earlier. They were 0.6% higher than in August.

One report holds many figures. Each answers a different question. This guide shows how to tell them apart, with September as the worked example. Our September 2026 CPI report recap covers what happened on the day.

The BLS publishes the report once a month at 08:30 Eastern Time. That is 13:30 in the UK on the dates below, but 12:30 in the few weeks of March and late October when US and UK clocks change on different days.

The October 2026 report is due on Tuesday 10 November 2026. The November report follows on 10 December 2026. The December report is due on 13 January 2027.

The first paragraph of the release gives the headline result.

The release holds eight tables. Table A sits inside the text. Tables 1 to 7 follow with the detail. They cover expenditure categories and special groups such as core. They also cover selected cities.

The main measure is the CPI-U, which covers all urban consumers. BLS says that population is over 90% of the US population. The release also carries the CPI-W, a second index for households that depend on wage or clerical work.

The CPI is an index, a single number that tracks prices against a base period. For September 2026 the index stood at 336.940, with the 1982 to 1984 average set at 100.

The monthly change compares one month with the one before. The 12-month change compares a month with the same month a year earlier. Month-on-month versus year-on-year inflation covers the difference in full.

September 2025 stood at 324.800. So 336.940 against 324.800 is a 12-month rise of 3.74%, which BLS reports as 3.7%.

Seasonal adjustment removes price changes that normally occur at about the same time every year. BLS headlines the seasonally adjusted figure for the monthly change, but reports the 12-month change before adjustment.

The chart shows both versions of the monthly change.

In January the unadjusted figure was 0.4%, against 0.2% adjusted. In August the order flipped, with 0.4% adjusted and 0.3% not adjusted. In June prices fell, by 0.4% adjusted and 0.3% not adjusted. September was 0.6% on both.

Before rounding, the figures were 0.649% adjusted and 0.585% not.

BLS notes that adjusted indexes can be revised for up to five years. It calls the unadjusted data more appropriate for escalation, meaning contracts that rise with the CPI.

Headline CPI is the all items index. Core CPI is the all items index less food and energy, which BLS calls "all items less food and energy". BLS describes food and energy prices as relatively volatile. Core versus headline inflation explains the split.

The chart shows what the index is made of, using the BLS relative importance weights for July 2026, the latest in the monthly release. Core makes up 79.114% of the index. Food is 13.540% and energy is 7.347%.

Shelter alone, the cost of housing, is 35.343%. Core goods are the goods other than food and energy. Other core services are the services other than shelter and energy. The three core bars add to 79.1%.

In September 2026 shelter rose 0.4% on the month and 3.2% over 12 months.

One point on the Federal Reserve (the Fed). Its 2% inflation goal is defined on the Personal Consumption Expenditures (PCE) Price Index, a different index from the CPI. What is PCE inflation? explains that index.

A component moves the index through its weight and its change together. Multiplying the two gives its contribution in percentage points. A large weight with a small change can matter as much as a small weight with a large change.

The weights drift as relative prices move. That is why the BLS annual table for December 2025 and the July 2026 figures differ.

September shows both cases. Energy is 7.347% of the index but rose 5.2% on the month. Gasoline, one part of energy, is 3.770% of the index and rose 9.1%.

The product is 0.34 points: 0.0377 times 9.1. The all items monthly rise was 0.65 points before rounding to one decimal place, so gasoline supplied about 53% of it. That is over half, which is what BLS attributes to it.

Shelter has the largest weight, but its 0.4% rise gives about 0.14 points, less than gasoline did.

Food was unchanged on the month. What is CPI? covers how the index is built.

The consensus estimate is a single forecast for a figure, compiled from forecasts published before the release. The surprise is the reported figure minus the consensus estimate. A positive surprise means prices rose by more than forecast.

The chart sets September's four headline figures against their consensus estimates. The all items monthly rise of 0.6% matched.

The 12-month rate of 3.7% was 0.1 point above the 3.6% estimate. Core rose 0.3% on the month against 0.2%. Over 12 months it rose 2.6% against 2.5%.

Both numbers are rounded to one decimal place, so a 0.1 surprise is a blunt measure. The September core monthly figure was 0.335% before rounding. It comes from core index levels of 337.765 in August and 338.896 in September, which are a different index from the all items 336.940.

The 0.2% consensus estimate could stand for anything from 0.15% to 0.25%. So the true gap lay between 0.085 and 0.185 points.

The steps below follow the order of the release.

The CPI report gives four headline figures, each with a job. The monthly figures cover the latest month. The 12-month figures cover the past year. The gap to the consensus estimate measures what was new.

The Bureau of Labor Statistics releases the CPI report at 08:30 Eastern Time. That is 13:30 in the UK on the next three release dates, 10 November, 10 December 2026 and 13 January 2027. The October 2026 report is due on Tuesday 10 November 2026.

Headline CPI covers all items. Core CPI leaves out food and energy, two components whose prices BLS calls relatively volatile. In September 2026 headline CPI rose 3.7% over 12 months and core CPI rose 2.6%. Core versus headline inflation explains why both are published.

The monthly changes BLS headlines are seasonally adjusted. The 12-month changes are reported before seasonal adjustment. In January 2026 the adjusted monthly change was 0.2% and the unadjusted change was 0.4%. The release carries both versions, so check which one a figure uses.

CPI above consensus means the reported figure was higher than the consensus estimate, the forecast compiled before the release. The gap is called the surprise. In September 2026 core CPI rose 0.3% on the month against the 0.2% consensus estimate, a surprise of 0.1 percentage point.

No. The Federal Reserve defines its 2% inflation goal on the PCE Price Index. The CPI is a different index. What is PCE inflation? explains the difference between the two.

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