Royal Mint has already begun producing the new coin at a rate of4,000 a minute with a target of having one billion ready for when they go into use.
The current £1 coin, which went into circulation in 1983, is being replaced over concerns it is too easy to copy.
It will remain in circulation alongside the new coin for six months before being taken out of use.
The Chancellor said: “With ground-breaking technology, developed in Wales, the new coin will help secure our economy and get rid of counterfeits. In a year’s time, the new coin, which will incorporate emblems from all four of our home nations, will line millions of pockets and purses around the UK.”
The design of the new coin, by a teenager from Walsall, was unveiled last year.
Royal Mint chief executive Adam Lawrence said the organisation was facing a “challenging but hugely exciting year” to prepare for the change to the new coin.
He added: “In modernising the iconic £1 coin we are helping to re-define the world of coinage for the future.”