The dollar plunged across the board on Wednesday after the Federal Reserve signalled an interest rate increase as early as June but slashed interest-rate projections over the next few years and downgraded its outlook for the US economy.
The greenback posted its largest one-day fall in six years against the euro and sterling, at one point falling as much as 3 percent versus the euro.
The dollar also dropped 3 percent versus the Swiss franc, posting its worst daily performance since Jan. 15, when the Swiss National Bank removed the franc's peg.
As expected, the US central bank dropped the word "patient" from its statement in terms of raising interest rates, but lowered its economic and inflation outlook for this year and sharply cut its projected interest rate path for the US economy.
"The message from the Fed is that the economy is not there yet to tolerate an imminent rate hike, which should reduce the chance of the dollar reaching parity against the euro any time soon," said Joe Manimbo, senior market analyst at Western Union Business Solutions in Washington.
In late trading, the dollar dropped 3.1 percent against the Swiss franc to 0.9752 franc, after earlier hitting a two-week low. It fell to three week-troughs against the yen and was last at 119.80, down 1.3 percent, the dollar's worst day since December 2-14.
The euro, meanwhile, hit two-week highs against the dollar and was last trading at $1.0898, up 2.8 percent.
The dollar also plummeted versus the Australian, New Zealand and Canadian dollars. The Aussie rose 2.5 percent vs the US dollar to US$0.7780.
Sterling rose above $1.50 against the dollar, up 1.8 percent.
Interest rate futures are pricing in a 67 percent chance that the first Fed rate hike will come in October, based on CME FedWatch, which tracks rate hike expectations using its Fed funds futures contracts.
Before the release of the Fed's post-policy-meeting statement, traders were betting the first rate hike would come in September.
"The Fed does not want the dollar to build on recent strength for now," said Alan Ruskin, global head of currency strategy at Deutsche Bank in New York."
"The burden of proof has shifted. The labour market data must prove that an early June tightening is warranted; in the meantime, the default is September or later."