The dollar tumbled on Wednesday after data showed that consumer prices in May rose less than economists expected, adding to bets that the Federal Reserve may begin cutting rates as soon as September.

Headline inflation was flat on the month, below expectations for a 0.1% gain. Core prices rose by 0.2%, below economists' projections for a 0.3% increase.

The dollar index was last down 0.63% on the day at 104.60. The euro gained 0.67% to $1.081. The dollar weakened 0.34% against the Japanese yen to 156.53 yen.

(Reporting By Karen Brettell)