The August figure compares with 3.3 percent in July and an average forecast among analysts of 3.3 percent in August as well, according to Bloomberg.
In core inflation, energy and food prices have been removed.
Including all types of consumer prices, the annual price increase in August was 3.4 percent according to the PCE measure, compared with the expected 3.7 percent.
PCE inflation is seen by the US Federal Reserve (Fed) as perhaps the most important indicator of inflationary pressure in the economy when making decisions about future policy rates. Unlike the CPI measure of inflation, which is based on a basket of goods, PCE inflation is calculated on what is actually consumed.
The Fed's inflation target is 2.0 percent.
