U.S. Inflation Holds at 3.4% in August as Monthly CPI Accelerates to 0.4%

U.S. consumer prices rose 0.4% in August, a sharp pickup from July, while the annual inflation rate held at 3.4%. The monthly increase was the fastest since May and showed that a steadier 12-month rate can mask meaningful changes in the prices households are paying from one month to the next.

Core inflation, which excludes food and energy, rose 0.3% for the month and 2.4% from a year earlier. That left the underlying measure cooler on a 12-month basis than in July, even as its monthly pace accelerated. The split gives the Federal Reserve a mixed inflation picture only days before its September policy meeting.

The Bureau of Labor Statistics’ Consumer Price Index release showed that gasoline was the largest source of the August pickup. Gasoline prices rose 3.9% and accounted for more than one-third of the increase in the all-items index, reversing part of the energy relief seen a month earlier.

Gasoline reverses July’s energy decline

The energy index rose 2.1% in August after falling 1.5% in July. Food prices increased a much smaller 0.1%, while shelter rose 0.3%. Those movements meant the headline acceleration was heavily influenced by energy, but it was not an energy-only story because housing costs and several service categories also moved higher.

July had looked quite different. BLS reported a 0.1% monthly rise in the CPI that month, with shelter accounting for roughly two-thirds of the increase and energy falling 1.5%. The gasoline index dropped 2.9% in July. August therefore brought a reversal in one of the most volatile parts of the consumer basket rather than a broad repeat of July’s pattern.

The 3.4% annual headline rate was unchanged from July. That stability matters because it shows that the larger August monthly increase did not immediately push the year-over-year figure higher. It does not, however, make the 0.4% monthly move irrelevant. Monthly readings can change direction quickly, particularly when gasoline and other energy prices swing, and the August report shows why the shorter-term and 12-month measures can send different signals at the same time.

For household budgets, the composition also matters. A rise in gasoline affects consumers directly at the pump and can be felt quickly, while shelter costs move more slowly through the CPI. Food’s 0.1% increase was comparatively restrained in August, limiting its contribution to the headline gain.

Core inflation cools annually but firms on the month

Excluding food and energy, prices rose 0.3% in August after a 0.2% increase in July. On a 12-month basis, core CPI eased to 2.4% from 2.5%. The latest figures therefore point to somewhat slower underlying inflation over the past year but a faster monthly pace at the end of that period.

That distinction is useful because a lower annual core rate does not mean price pressure disappeared in August. The monthly core figure captures a range of nonfood, nonenergy categories and came in above July’s pace. At the same time, the easing from 2.5% to 2.4% over 12 months suggests the longer-run core measure continued to move in the opposite direction from the month’s acceleration.

The headline and core readings also answer different questions. Headline CPI captures the full consumer basket and therefore reflects the immediate effect of a gasoline rebound. Core CPI strips out food and energy to reduce some of that volatility. Neither measure should be read in isolation, and the August report is a particularly clear example: headline inflation accelerated monthly, annual headline inflation was unchanged, monthly core inflation firmed, and annual core inflation eased.

August’s result follows an unusually volatile stretch for headline inflation. The all-items CPI fell 0.4% in June before rising 0.1% in July and 0.4% in August. Much of that month-to-month movement has been tied to energy. Looking across the three months helps separate the current inflation rate from a single month’s change without assuming that August’s pace will necessarily persist.

Report lands just before the Fed’s September meeting

The inflation data arrive ahead of the Federal Open Market Committee’s September 15-16 meeting, which is also scheduled to include a new Summary of Economic Projections. At its July meeting, the Fed held the federal funds target range at 3.5% to 3.75% and said inflation remained elevated relative to its 2% goal.

The July decision passed by a 9-3 vote. Beth Hammack, Neel Kashkari and Lorie Logan dissented because they preferred a quarter-percentage-point increase. Minutes from that meeting said several participants favored a 25-basis-point increase, while most supported holding the rate steady so that additional information could clarify the inflation outlook.

August CPI is now part of that additional information. It does not settle the policy decision by itself. The Fed’s 2% inflation objective is framed around the personal consumption expenditures price index rather than CPI, and policymakers also weigh labor-market conditions, economic activity and financial conditions. Still, the faster monthly headline and core readings give officials a fresh measure of price pressure immediately before they meet.

The report leaves policymakers with two competing signals inside the same release: annual core inflation moved lower, but the latest monthly headline and core increases were both faster than in July. The FOMC is scheduled to meet September 15-16, making the August CPI one of the final major inflation readings available before that decision.