Analysts had expected an average annual price increase of 3.4 percent, according to Bloomberg.
Underlying inflation fell from 2.5 to 2.4 percent, also as expected.
The figure comes ahead of the US central bank's, the Fed's, interest rate decision next week, September 16. Analysts are divided on whether there will be an interest rate hike or not.
The fixed-income market is now expecting a 90 percent probability of an interest rate hike. Before the figure was released, that probability was 67 percent.
