King Charles, 73, automatically became king on the death of his mother Queen Elizabeth last month, but the grand coronation ceremony for him and his wife Camilla, who will be crowned queen, will now take place on Saturday, May 6.
"The coronation will reflect the monarch’s role today and look towards the future, while being rooted in longstanding traditions and pageantry," the palace said in a statement.
The ceremony, a solemn and religious event which will be conducted by the Archbishop of Canterbury, the spiritual head of the Anglican Communion, usually comes several months after the accession of the new monarch.
Kings and queens of England, and later Britain and the United Kingdom, have been crowned at Westminster Abbey since William the Conqueror in 1066.
Charles is the 41st monarch in a line that traces its origins back to William, and he will be the oldest monarch to be crowned.
His mother, who died aged 96 at her Scottish holiday home, holds the record for the longest reign at 70 years.
Elizabeth's coronation as queen on June 2, 1953 was the first to be televised and was regarded as a milestone in modernizing the monarchy, a move that her husband Prince Philip was said to have pushed for strongly.
Charles is king and head of state not only of the United Kingdom but of 14 other realms including Australia, Canada, Jamaica, New Zealand and Papua New Guinea.