The US dollar has traded higher against the euro and lower against the pound, which benefited from the Bank of England's upgrade of Britain's economic growth forecasts and tweaked policy guidance.
The yen firmed, pushing both the dollar and the euro lower.
Around 2200 GMT Wednesday (0900 AEDT Thursday), the euro bought $US1.3593, down from $US1.3638 late Tuesday.
The US dollar fell against the Japanese currency, trading at Y102.50 compared with Y102.64. The euro dropped to Y139.33 from Y139.99.
Both currencies swooned against the British pound. Sterling bought $US1.6593, up from $US1.6451. The euro fell to 0.8191 pounds from 0.8287.
"With no US economic data released today, there was very little consistency in the performance of the greenback," said Kathy Lien of BK Asset Management.
Lien said the pound was in high demand and traded higher against all the major currencies after the Bank of England on Wednesday ramped up its economic growth forecasts - to 3.4 per cent for 2014 - but vowed to keep interest rates low, dropping the 7.0 per cent unemployment rate threshold earlier suggested for a rate hike.
"We believe there's further room to the upside," Lien said.
"From a fundamental perspective, investors are pleased to see the central bank accepting its mistake of tying monetary policy to a specific level of unemployment."
The US dollar picked up against the Swiss currency, buying 0.9004 Swiss francs compared with 0.8983 francs on Tuesday.
