The Consumer Price Index, which measures a basket of goods as well as energy and housing costs, rose 4.2% from a year earlier. A Dow Jones survey had expected a 3.6% increase. The month-to-month gain was 0.8%, against the expected 0.2%.

The increase in the annual headline CPI rate was the fastest since September 2008, while the monthly gain in core inflation was the largest since 1981.

Energy prices overall jumped 25% from a year earlier, including a 49.6% increase for gasoline and 37.3% for fuel oil. That came even though most energy categories saw a decline in April.