The service will be conducted by the Archbishop of Canterbury and will take place at Westminster Abbey, where his mother's funeral took place.
Queen Consort Camilla will be crowned alongside King Charles.
Plans for the major event are known by the codename Operation Golden Orb, which sets out the blueprint for the service and the pageantry surrounding it.
The palace said the ceremony will be “rooted in long-standing traditions and pageantry” but also “reflect the monarch’s role today and look towards the future”. It described it as a "solemn religious service, together with an occasion for celebration and pageantry".
In a deeply religious service, King Charles will be anointed with holy oil, receive the orb, coronation ring and sceptre, be crowned with the majestic St Edward’s Crown and blessed during the historic ceremony.
The monarch is the head of the Church of England so it will be an Anglican service, but it is expected to be more inclusive of multi-faith Britain than past coronations.
The queen consort will also be anointed with holy oil and crowned, as the Queen Mother was when she was crowned in 1937.
In a statement, the palace said: “Buckingham Palace is pleased to announce that the coronation of His Majesty The King will take place on Saturday 6th May 2023.
“The coronation ceremony will take place at Westminster Abbey, London, and will be conducted by the Archbishop of Canterbury.
“The ceremony will see His Majesty King Charles III crowned alongside the Queen Consort.
“The coronation will reflect the monarch’s role today and look towards the future, while being rooted in long-standing traditions and pageantry.”
The coronation falls on the birthday of the Duke and Duchess of Sussex’s son Archie, who will turn four. It has not yet been confirmed who will attend the ceremony and whether or not Prince Harry and his wife Meghan will be among those invited.
Traditional coronation with a modern twist
It is understood that the ceremony will include the same core elements of the traditional service, which has retained a similar structure for more than 1,000 years, while also recognising the spirit of our times.
For the last 900 years, the ceremony has taken place at Westminster Abbey and since 1066, the service has almost always been conducted by the Archbishop of Canterbury.
The coronation is expected to be on a smaller scale and shorter than the late queen's coronation in 1953, with suggestions that it could last just one hour, down from more than three.
Guest numbers will be reduced from 8,000 to around 2,000, with peers expected to wear suits and dresses instead of ceremonial robes, and a number of rituals, such as the presentation of gold ingots, axed.
Coronations have not traditionally been held on a weekend, with the late queen’s taking place on a Tuesday. The palace has yet to comment on whether there will be any arrangements for a bank holiday. It had been speculated that the date would be June 3, but that would have clashed with the FA Cup final.
King Charles III through the years — in pictures
Further details are due to be released in due course, but the government and the royal household will be conscious of the scale of the coronation in light of the cost-of-living crisis facing the UK.
Security will be heightened given the high-profile nature of the day.
The king is expected to sign a proclamation formally declaring the date of the coronation at a meeting of the Privy Council later this year.
He will be anointed by the Archbishop and take his oath to “maintain and preserve inviolably the settlement of the Church of England, and the doctrine worship, discipline, and government thereof, as the law established in England”.
The queen consort will be crowned and take her place on a throne.
Queen's masterstroke to give Camilla the green light to be queen
On the eve of her Platinum Jubilee in February 2022, Queen Elizabeth endorsed the then-Duchess of Cornwall to be known as queen consort when the time came.
Royal aides insisted, when she married Prince Charles, that Camilla did not want to be queen and said originally that she “intended” to be known instead as Princess Consort — the first in British history — when her husband acceded to the throne.
The wife of a king automatically becomes a queen and only a change in legislation would prevent her from doing so, but there had been much controversy over whether Camilla would use the title, being Charles’s former mistress.
The royal website used to declare: “A Queen Consort is crowned with the King, in a similar but simpler ceremony.”
But following the prince’s marriage to Camilla it added the get-out clause “unless decided otherwise”.
The Duke of Norfolk, who organised the queen’s funeral, also has the role of staging the coronation.
He was recently banned from driving for six months after pleading guilty to using his mobile phone behind the wheel — despite claiming he needed his licence to arrange the forthcoming ceremony.
Queen's coronation brought much needed boost to postwar Britain
The late queen’s coronation took place on June 2, 1953 — 16 months after she became monarch.
It was a carnival of celebration and a morale boost for a nation starved of pageantry after the Second World War.
People began to bed down in the streets of London as early as 48 hours before the service, just to make sure they had a standing place to watch the queen pass by in the gold state coach in a grand procession.
By the Monday evening, in pouring rain and driving wind, half a million people were already lining the procession route.
Special seating structures were built inside the church to increase the usual congregation from 2,000 to 8,000.
Prince Charles, who was only four at the time, attended the service.
He has recalled his mother saying goodnight to him the night before while wearing the crown so she could get used to its weight on her head.
He remembered “thousands of people gathered in The Mall outside Buckingham Palace chanting ‘We want the Queen’ and keeping me awake at night”.
The 1953 coronation was shared with a wider audience through the relatively new medium of television, which came of age with the screening of the ceremony for the first time.
An estimated 27 million people in Britain alone watched the ceremony live on their black and white TVs and the images were also beamed around the world.